Most manlands aren't good enough to warrant the ETB tapped that most of them have. Raging Ravine and Creeping Tar Pit are the only ETBT manlands I run in any deck; Tar Pit is great at killing 'walkers, and activating Ravine multiple times can make it quite large (and the deck I run it in has an Epic spell, so I need lands to do things once that's resolved).
For the ones that don't enter tapped, Inkmoth and Blinkmoth are both decent for having evasion (and having both means one can buff the other). Mishra's Factory can block as a 3/3 (or attack if it's got vigilance) for functionally 2 mana which is also quite good. Mutavault is best if you've got stuff that cares about creature types, like Yuriko, the Tiger's Shadow.
For the ones that don't enter tapped, Inkmoth and Blinkmoth are both decent for having evasion (and having both means one can buff the other). Mishra's Factory can block as a 3/3 (or attack if it's got vigilance) for functionally 2 mana which is also quite good. Mutavault is best if you've got stuff that cares about creature types, like Yuriko, the Tiger's Shadow.
Two Score, Minus Two or: A Stargate Tail
(Image by totallynotabrony)