I've noticed there are a couple of villian strategies on how to beat the villian out on flamethrower's post but are there any more?
Is there a particular villain you'd like help with, or are you just generally looking for villain guides?
Based on my expeience, most of the villains can be beaten by the same general strategy and don’t need their own guide.
Bring a lot of damage (this can include support that increases damage, but preferably not very many). If the villain has any problematic ongoings (a lot don’t), bring some heroes that destroy them (not every hero, but more than 1), and the same goes for the environment. Remove/attack/otherwise get rid of cards that seem at least moderately threatening and do damage to the villain as a secondary goal. It doesn’t work for everything, but I’ve beaten every villain and played countless games, and believe it should be effective on about 2/3 of them without much other strategy.
A lot of villains cetainly need more thought, and I have used many tips and tricks found on on these forums. They aren’t always in guides, but I just do a search for the villain name or a particular card. That works pretty well. There are a lot of useful discussions on these forums.
I think most of the decisions that SotM villains present are related more to (tactical) threat assessment than particular strategies. You often have to decide how to pursue the strategy of your hero deck in light of the threats presented (for example, is the current threat level bad enough that I should play a one-shot to help bring it down or should I play an ongoing to prepare for future threats).
That said, many villans have at least a few cards or a flip mechanic that impact your strategy. For Omnitron, knowing that he has Terraforming, Bomb, Flechettes, and Singularity makes a big difference in how we play. For Dawn the flip mechanic has a big impact. For Vengeance 5, you often want to choose a villain deck to focus down so you can start turning the tide. I think at least a paragraph or two could be written up about most villains (and some environments) with regards to strategy.
Still, most of the strategy part of the game will be implementing your hero's strategy.