The Regis, namely Regice, Regirock and Registeel are largely mediocre. On its own Regice is pretty terrible. Its a defensive tank like its compatriots but unlike them,Regice was actually decent as an Ice type. As a pure Ice attacker it ranked third, behind only Jynx and Articuno. You could have made a case to use Regice back then.
Then Generation 4 came out and that was the end of Regice’s time as an adequate attacker. Mamoswine and Weavile are far better than Regice who is only better at taking hits than the other two. Regice has 182 attack, 309 defence and 190 stamina. 309 defence is the 4th best in the game but its attack is where it lags behind the rest. Regice is best collected, like the rest.
|Resists||Weak To||Normal Damage|
On its own, Ice is a pretty bad type defensively. Its sole resistance is to itself and it comes with 4 weaknesses. Fighting is a weakness common among the Regis, so you can stick with the same Fighting types you used for the others.
Frost Breath is the better of the two moves, gets STAB and all. Rock Smash is dangerous if you’re using a Rock or Steel type.
Blizzard is the best move, like Frost Breath it gets STAB. Focus Blast , like Rock Smash is going to pose a threat to Rock and Steel types so be careful of that. Earthquake has the same effect but its the worst of the 3 moves by far.
Assembling The Team
Fighting types would be the safest. Rock and Steel just need to be careful of any charge move other than Blizzard. Fire types just need to avoid Earthquake, unless you’re using Moltres or Ho-oh.
Being Steel/Psychic, Metagross can at least sleep easy knowing Regice’s Fighting moves do neutral damage to it. Earthquake still hurts, just know when its coming and avoid it. For Metagross go with Bullet Punch and Meteor Mash.
The current best Fire type in the game, Moltres’ Fire/Flying typing makes it resistant to Regice’s Fighting and Ground moves, while it only takes neutral damage from Ice. You can use any moveset that has two Fire moves but the best moves will be Fire Spin and Overheat.
Machamp is the best Fighting type, still is after 4 Generations. You can even use its Steel moves on Regice but you could honestly do better with Machamp’s Fighting moves. Any combination but the best is Counter and Dynamic Punch.
As of now its the best Rock type in the game, and being strong against Ice, Rampardos is a hard hitting counter to Regice. This works best if Regice is only using its Ice moves given Rock’s weakness to Fighting and Ground. For Rampardos’ moves, go with Smack Down and Rock Slide.
Its not worth using in the game, its only worth collecting. However Niantic will probably release a shiny version sometime in the future so keep an eye out for that.