Rider and Ramos stuff covers a lot to be honest. Arachnids are decent schemers depending a little on your board. Watchers may be necessary in some situations, being able to transfer power to push themselves is invaluable sometimes, they're hard to lock down.
I haven't played soulstone miners since they were nerfed so not sure on them anymore.
I love the guardian and a riot breaker can be good in certain matchups. The new box with five models where you're likely to only use two is a tough sell for me though. I'd honestly look at a proxy or just limit myself to the stuff you already have. If you can split that box with someone, do it!