I agree Mike, this is a too long list with a lot of very niche ideas. Most of it much more suitable for a small metal or resin figure manufacturer who could cast on demand. I reckon Planet of the Apes, Star Wars like and Starship troopers like sets might be a goer. Would be nice to see Starship Trooper like bugs or the classic xenomorphs from the alien movies. Of course, all of this might have insurmountable intellectual property issues. I've been contemplating getting the space devils from Khurasan (I think) but at a nominal 15/18 they might not look that menacing against 20mm figs.

Action Fleet did Starship Troopers and Aliens and Star Wars many years ago, their stuff is still sold in eBay and it's very nice and durable. They were sold as toys and so have a lot of play value. I got some when they hit close out in the stores. The are about the size of "large" 1/72nd scale figures.

There have been a lot of Aliens toys out there and not all of them were licensed. The general shape of the alien seems to be okay to make without a license, but I am no lawyer so don't listen to me.
But how large is an Alien? So they are around if you look for them.

The nice thing about the Action Fleet stuff is all the figures and vehicles are the same scale. You can use Starship Troopers to fight aliens or Imperial Storm Troopers.

Just do an ebay search for "Action Fleet" and they will show up.

Mike Bunkermeister Creek