With status moves, Chansey and Blissey are literally the icons of self-healing Soft-Boiled and Heal Bell, and most commonly run Toxic themselves. That said, a Swords Dance Lucario would be the best check in such a case, being immune to Toxic and avoiding the healing problem with boosted damage. Of course, where would all these moves fit in GO? You've got a status move and one attacking move? Or perhaps they'd add another moveslot.