Well I'm afraid there are not many options sf.
we have chansey, Blissey and Celebi.
Obviously the choice is yours and it depends on how they fit into your team but ill give some incide info.
Blissey
Ok as a heal bell abuser she is ok personally I prefer Chansey but then again Blissey has leftovers going for her.
I suggest using both Chansey and Blissey as the support role as its personal preferance it comes down to.
Chansey
Ive used Chansey as a heal bell user in both Ou and Ubers and imo it just beats Blissey at the role as it has that extra bulk making it perfect for support but then it looses out on leftovers.
Celebi
I wouldnt use Celebi not in Ou anymore at least Gensect and so many other Pokemon beat it with ease and I have only used the heal bell set once before Gensect was released and it was Ok but Celebi just seemed a bit frail for me and wasnt worth wasting a slot for, an offencive set is better suited imo.
Chansey (F) @ Eviolite
Trait: Natural Cure
EVs: 252 HP / 252 Def / 4 SDef
Careful Nature
- Softboiled
- Heal Bell
- Seismic Toss
- Thunder Wave/Stealth Rock
Blissey (F) @ Leftovers
Trait: Natural Cure
EVs: 252 HP / 252 Def / 4 SDef
Bold Nature
- Softboiled/Wish
- Toxic
- Heal Bell
- Flamethrower/Seismic Toss
Celebi @ Leftovers
Trait: Natural Cure
EVs: 252 HP / 220 Def / 36 Spd
Bold Nature
- Heal Bell
- Leech Seed
- Recover
- Giga Drain
Pesonally I would use chansey but by all means try out Blissey and if you have to Celebi.