Hi,where can I find the thumper entity from half life on gmod?

If you mean where you spawn it from (the thumper entity), it’s in ‘Entities/Half Life 2/Thumper’ in the Q menu

If you mean the model for it, the model is ‘models/props_combine/combinethumper002.mdl’

Hope this helped!

Where can you find the thumper entity in garry’s mod folder?

Well, you can’t find entities in the spawn list in Garry’s Mod, you can only spawn them from the ‘Entities’ tab.
But, if you meant you wanted to find the MODEL for the thumper in the spawn list, you shouldn’t be looking in the Garry’s Mod folder. You should look in the Half Life 2 folder (assuming you have Half Life 2 installed). Just go to Browse/Games/Half-Life 2/props_combine and look in there until you can find it.

But, if you’re looking in the STEAM Garry’s mod folder (C:\Program Files (x86)\Steam\SteamApps\common\GarrysMod\garrysmod), it isn’t there.

That’s because all the stuff for GMod is in garrysmod_dir.vpk (which should be in the folder path I posted above). You can open that file if you want using something like GCFScape.