>>45478417The top 5 teammates for Regieleki are:
1. Landorus-T
2. Magearna
3. Tapu Koko
4. Dragapult
5. Swampert
You can't really go wrong with Swampert. Give it Flip Turn and it can easily bring in Regieleki. Basically, it's bulky enough to take a hit from just about everything, slow switch into Regieleki, which can then force a kill since it got in for free. Swampert also kills other Ground types with Ice Punch/Ice Beam (1HKO on Lando, Garchomp), or deals ~60% switching with Flip Turn. Swampert can also serve as a useful switch-in to other Regielekis, something your team is weak to.