Warhammer 40k

So far I've just kind of been randomly acquiring things based on what looks cool to me in the moment

This is what I do, hasn’t done me wrong. If 82 dudes with jump packs is wrong then I don’t give a fuck what’s right.

Not too familiar with orks, but gretchin look to be a good add for some objective capturing and blocking fodder, maybe grab something to hold your home objective. All depends on if you’re looking to capture points and grab mission objectives, or if you’re looking to play accurate to the lore and just drown your opponents in the WAAAAAAAAGH! There are no wrong answers.

2x10 grots is definitely a good choice. You can get a beadtboss on squigasaur for the squighogs to get a really high treat blob. Getting some basic Ork Boyz is also always good if you are getting into orks. Eventually you will want more trukks and a warboss. But getting what you vibe with is definitely the general best way to go.

There are also a couple Ork discords you can join if you want.

Grots are always a useful addition.
What to suggest next really depends on whether you're looking to build a specific force (e.g. green tide) or have fun with whatever takes your fancy.

I own Two Stompa. I should not advise on orks. It’s irresponsible of me to.

That said you should buy several Stompa.

Also looking at what you have komandos or some form of heavy weapons may be helpful at 1k pt