So you want to play a gnome?

General Overview

Scarterran dwarves are honestly not very different from most other fantasy dwarves and Scarterran elves are clearly pretty similar to Warhammer Fantasy elves. Scarterran gnomes diverge from most other fantasy gnomes. Not to the point that they are unrecognizable, but it is worth reading the article entry on gnomes.
Scarterran gnomes are not hedonistic trickster or crazy tinkerers like 5th edition D&D gnomes though there are individual gnomes who fit this mold. They are not illusion loving hobbits like in 2nd edition D&D gnomes but a a few individuals fit this mold. Scarterran gnomes have some similarities with Tolkien's hobbits, but it would be a gross oversimplification to make a one-to-one comparison between Scarterran gnomes and Middle Earth hobbits.
Scarterran gnomes, in general, are diplomatic talkers. Part of this is because Mera wanted to create a race of nonthreatening diplomats to engineer piece between all races and part of this is because when you are small and easy to physically dominate, you better be able to talk your way out of trouble.
Most gnomes have strong ties to their families and communities but they have a curiosity for other cultures and are generally open minded and friendly so they tend to get along with other races, or at least they make an effort to get along with other races and they are happy to expand their proverbial families and communities in a wider circle. Gnomes player character adventurers can easily adopt the other members of their adventuring party as a surrogate family.

Vusnitt version 2 by Me using Hero Forge

There are some misanthropic gnomes with tragic or stunted backgrounds. Even then, these gnomes are social in their own way. Instead of forming genuine ties of family and friendship, more sociopathic gnomes view other people as puppets and pawns to impersonally wield to accomplish their goals.
Some gnomes can even split the difference, they have a small group of trusted friends and allies but view the general population as unimportant mooks to manipulate as needed.

Because of the very powerful social bonus gnomes receives, from a min-maxing perspective a gnome can be very effective character by frontloading your character with high social attributes and lots of social abilities like Empathy, Etiquette, Expression, Performance and Politics.
Even if your gnome character is not a socially oriented diplomat and supreme talker, almost all gnome characters are going to value their social connections greatly. Even players of gnomes with mediocre or below average social abilities should consider taking a fair number of social Merits as even comparatively introverted gnomes value their social ties.
Assuming your gnome character is relatively good natured and disposed to be a heroic player character, your gnome is probably a member of the Order of Delas or will get an invitation to join them soon enough. If your gnome character is darker, he probably has a network of criminal contact and ne'er-do-wells. Gnomes are complex individuals and a gnome character can easily have a mix of respectable and disreputable social connections. Even the Order of Delas has the Dagger of Delas.
There are exceptions, but most gnomes are modest, or at least put up a front of false modesty. There are not many feudal gnome lords or gnome chieftains in Scarterra but a great many lords and chieftains have a clever gnome advisor. Maybe the gnome advisor is an extremely loyal steadfast supporter of the ruler or maybe the gnome is a Machiavellian master manipulating his lord on invisible puppet strings but either way, they are probably very good at their jobs.
Gnomes are a little bit more likely to take the head position in priesthoods and guilds but even in these settings, gnomes are commonly the quiet but indispensable supporters of the leaders.
In an adventuring party, gnomes are frequently likely to take a supporting role though they often take center stage during negotiations and diplomatic actions.

How gnomish is your gnome?

Gnomes don't have any homelands of their own, or at least not any large homelands. Gnomes tend to assimilate into other cultures and they are damn good at doing this.
Sometimes gnomes live in all gnome village or districts. These gnomes believe that good fences make good neighbors. They pay their taxes and don't make waves with the local non-gnome rulers. They are friendly and polite but somewhat distant from their non-gnome neighbors.
Other gnomes fully embrace the culture of the non-gnome lands they inhabit. They mix with non-gnome more than with other gnomes. In a lot of cases, these assimilated gnome are more enthusiastic about their patriotism, cultural practices, and even internalize the cultural biases and prejudices of the local area more than the local humans, dwarves, or elves do.
Some gnomes fall in between of course. Other gnomes are consummate travelers and love to immerse themselves in many different cultures and they will adapt many cultural tropes from varied sources into their daily lives and general outlook. There is no wrong to play a gnome with regards to assimilation but you as a player should have at least have a vague idea of what tack your gnome takes with other cultures so you can remain fairly consistent.

So you want to play a Rogue/Expert? who is also a gnome?

It is not hard to justify a gnome that is learned in many things. Most gnomes are literate and like books. Gnomes also are social and love to absorb oral lore. Whatever a gnomes area of expertise is (or desired area of expertise is), a gnome is equally happy taking on gnome apprentices or sharing their wisdom with non-gnomes. Gnomes are equally happy seeking out gnome teachers or studying under non-gnomes.
Gnomes might be jack of all trades types when it comes to their knowledge or they might be hyper focused experts on a small number of aspects of specific lore. You can think of an expert character archetype for a human, a gnome can probably do it just fine.

Kasailini Version 2 by Me using Hero Forge

Gnomes are generally socially oriented so a socially oriented gnome expert can be very powerful from a min-max perspective. A political gnome expert would be somewhat similar to Tyrion from Game of Thrones, though most Scarterran gnomes would be a less prideful and more willing to step into the shadows than Tyrion. Perhaps some kind of Tyrion/Varys gestalt would be most appropriate for a Scarterran gnome? Whether they use their powers for good or evil is up to the gnome in question.
Scarterran gnomes are a reasonable thematic fit for more physically oriented D&D style rogues. Anything a halfling rogue can do in D&D, a Scarterran gnome rogue can probably do in Scarterra d10 and the gnome in question is going to be great at verbal con games to boot.

In Scarterra, gnomes are famous, or even infamous for their silver tongues. This means other Scarterrans are likely to have their guard up around gnomes if the gnomes start sounding the least bit fishy. But to be the player of a great gnome con artist, you have to think like a Scarterran gnome. Gnomes can use reverse psychology or incept a mark to make them think the gnome's idea is their own. Gnomes often do well in social situations because they ferret out what the other person wants and figures out how to offer it to them.

So you want to play a divine magic caster? who is also a gnome?

A plurality of gnomes worship Mera primarily though gnomes keep a wide variety of religious practices and are regularly seen in the priesthoods of almost the entire Nonagon with the exception that you almost never see a gnome Testers.
Unless they are deliberately rebelling against or compensating for gnome cultural gnorms....er norms, most gnome priests and priestesses often play temple politics heavily and often end up in charge of their temple or advising the people in charge.
Being small and silver tongued really has no direct bearing on divine spell casting, so gnomes can and do practice any sort of theurgy but it is character-appropriate for gnomes to focus on the Hearth Wisdom or Theology/Enigmas based magics because gnomes are likely to develop these skills to a high level.

Ragani portrait by Eron12 using Hero Forge

So you want to play a mage who is also a gnome?

by Me using Hero Forge

Most gnome mages in Scarterra practice some form of wizardry, especially classical hermetic wizardry or folk magic, but nothing stops you from playing a gnome sorceress, or a gnome rune caster, or a gnome warlock.
Being small does not impair a gnome from casting arcane magic. You can pretty much justify any magical school or schools you want for a gnome mage. Gnome mages can be magical jack-of-all-trades types, or they can be hyper specialized.
Some gnome mages focus on socially oriented magic such as enchantment spells to play to their social strengths while others pick up more violent spells such as Invocation to make up for their physical shortcomings.
Many gnome mages gravitate towards Illusion magic as it appeals to non-violent gnomes, subtle manipulative gnomes, and flamboyant showy gnomes alike.

So you want to play a warrior? who is also a gnome

From a min-max perspective, playing a gnome warrior is challenging. Realistically, a gnome warrior is hampered by a lack of reach but due to the The Rule of Playability, reach is rarely a game factor in Scarterra d10. That said, a gnome's strength penalty is a significant handicap for warriors. Sometimes a gnome's reduced movement rate is inconvenient in less static combat situations with a lot of pursuits.
Maybe you are the sort of player that likes playing a suboptimal character, but even if you are not that sort, you can be an effective Scarterran gnome warrior if you think like a Scarterran gnome.
While Master Splinter from TMNT does not exist in Scarterra, I imagine Scarterran gnomes would agree with his teachings.

by Me using Hero Forge

“The first rule of being a ninja is, 'Do no harm.' Unless you mean to do harm. Then do lots of harm.”
-Master Splinter, TMNT 2012

Gnomes love peace and try to avoid harming others but when they are pushed to war, they fight dirty and with little mercy, fighting to utterly destroy their foes. They plan ambushes and sneak attacks, they will set traps ahead of time, they will utilize deadly poisons, deploy psychological tricks, and capitalize on any and every tactical advantage they can.
In addition to normal combat skills, a gnome warrior should dip into the expert subtype to load up on abilities that help set the battlefield such as a high Stealth rating with a specialty in ambushes, Hearth Wisdom with a specialty in poisons, Legerdemain with a specialty in concealed weapons, and Empathy with a specialty in fears or triggers are all good arrows to have in a gnome warrior's metaphorical quiver.