If you've got some community day mons, Counter/Blast Burn Blaziken is good, as is Frenzy Plant Torterra. Earth Power Flygon is a good cheap Ground Pokemon, but you'd have to be extra careful with rock moves cause of your Gyarados. We're about to have Rhyhorn day, which should give you plenty of great Rhyperior, and with some planning, you should have one to qualify for this league.
Good tips! Sadly both my blaz and tort are around 1500 CP and double bad moves however I do have a decent rhyperior. Which moves do you suggest?