(I hope this doesn't count as advertising and if it does, mods, feel free to delete but) you can search pkmncards.com and use the advanced search feature to filter for steel Pokemon in whichever format you're playing. Then scroll through until you find what you're looking for. For this example here's a search link that searches for all Metal Pokemon in the current standard format: https://pkmncards.com/?s=t:pokemon++c:m+f:bkt-on-standard-2018&display=scan&sort=date
It displays the cards as images so it's really easy to look through to find what you want.
For big attackers, yeah. Though if you can afford a single source of [M] Energy, Kartana-GX becomes an option. If you can make room for Counter Energy, then Cobalion (STS) could work.