Blissey Movesets

Wish Blissey-Calm Nature-Leftovers
Wish
Protect/Softboiled
Ice Beam/Flamethrower
Toxic

Blissey is arguably the best special wall in the game. Wish and Protect allow you to heal Blissey and teammates. Toxic is a great move for this set, which is primarily for stalling. Flamethrower hits most Steels (which are immune to Toxic) for super effectively damage. Unfortunately Heatran is immune to both of these move and is resistant to Ice Beam, which is a good option for Dragons and Dugtrio. Flamethrower is also 4x super effective ageist Scizor, the number one threat since the release of Platinum.

Support-Calm Nature-Leftovers
Aromatherapy
Ice Beam
Thunder Wave/Toxic
Softboiled

This moveset is for helping your teammates. Aromatherapy heals your team of all statuses. Thunder Wave cripples the opponent by halving their speed and creating a 1/3 chance of them not being able to attack. Softboiled allows you to heal Blissey as well as teammates

Charm-Calm Nature-Leftovers
Charm
Ice Beam
Light Screen
Softboiled

With Charm you will force a lot of switches so it's best to take advantage of Spikes and/or Stealth Rock. Switch in on a Special Attacker and when a Physical Attacker switches in to counter Blissey, use Charm, which will most likely cause them to switch. As that Pokemon switches out you can then use Light Screen to support teammates.