Second move on Raikou?

The only choice you have is shadow ball which makes it a worst version of Mewtwo with shadow ball, and it will be useful in pvp if the opponent use a ground type.

Better PvP coverage is what it's there for. In raids there are better ghost-type attackers and Raikou serves better as an electric attacker. In PvP it could be a fun surprise, I imagine you'd catch a few people off-guard.

I have a Raikou with TS/WC/SB I want to take for a spin in Ultra League but don't know who else to include in the team. I'd be open to suggestions.

Raikou is on my gym team. It is a good generalist. Shadow Ball would give it a little better coverage.

I did it, it's not bad. Definitely helps out against those pesky Metagross.

I think if you'll regularly use it for PvP the second move is worth the investment. In PvE for a raid generalist you're paying a lot for a move you're unlikely to use very often (it will be a very rare day that just swapping out to a different Pokemon in your team isn't a better/easier option). If you're swimming in resources though it's not the worst investment you could make

Its electric...just dance with the type that brought you