I know nothing about Gmod but every time I see stuff like this it makes me want to try it out. The only problem is I dont know if it costs anything to download or get models or something.

Ten bucks on Steam, all model packs are free, same for the maps and tools. All you need to do to get the models is subscribe to them via the workshop, same for the others.

Ragdoll Resizer tool. Look it up in the workshop with the 'Top Rated All Time' filter on.

When you resize them, they follow the movements of the normal sized ragdoll. However, don't move it from the 'center of it's animation', otherwise the resized one will rocket off to who-knows-where. Just a note though that the limit on how big you can make them varies on not only the ragdolls size, but also the open area and the airspace that each map has. Flatgrass has the largest airspace, allowing some ragdolls to be set to massive sizes. However, if you make them too big, you won't be able to grab the resized 'prop' to relocate it. Also note on where the skybox of each map is as well. You don't have to worry too much if it's below the ground, but above and you're gonna have a skybox version of the resized ragdoll clipping into the main map if you set the resizer too high.