Sableye
I see that you say that sableye dies too easily.
Consider this: Sableye has one weakness: fairy. It also has Prankster, which enables any non-attack move to go first. Mega-Sableye is rarely used, but it's multipurpose. Regular sableye is used to set up will o wisp, and stalling the opponents to death with various moves, and Mega Sableye is used to bounce back hazards such as leech seed, stealth rock, and more moves such as will o wisp, toxic, and many others. Sableye's my first suggestion. It doesn't need speed due to prankster.
Sableye @ Leftovers
Ability: Prankster
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
- Taunt
- Will-O-Wisp
- Recover
- Knock Off
Ferrothorn
Ferrothorn is a huge pain to fight on any front.
Running a hazard Ferrothorn works against most physical sweepers. Its ability, Iron Barbs, takes away 1/16 of health on contact, and Rocky Helmet as a held item takes away 1/6. it is also capable of setting up hazards such as spikes.
Ferrothorn @ Rocky Helmet
Ability: Iron Barbs
EVs: 252 HP / 172 Atk / 84 Def
Brave Nature
- Spikes
- Gyro Ball
- Stealth Rock
- Explosion/Protect
Whimsicott
Another prakster runner, but with a more favorable movepool and more weaknesses. Whimsicott is capable of setting up stun spore, leech seed, and substitute, and leftovers+leech seed can be up to 1/5-1/4 HP recovery each turn. Encore in this set can be replaced with moonblast for a counter to any taunters.
Whimsicott @ Leftovers
Ability: Prankster
EVs: 252 HP / 252 Def / 4 SpD
Bold Nature
- Leech Seed
- Substitute
- Encore
- Stun Spore
My Personal Favorite: Roserade
Surprisingly, I haven't seen much of Roserade these days, but I use one with almost any setup team. Roserade efficiently sets up toxic spikes and leech seed before being killed. Yes, roserade can only take one or two hits from M-Charizard, but with it's EV spread, it's almost impossible to OHKO it before it sets up toxic spikes. An extra turn to set leech seed in place and you're good.
Roserade is a presonal favorite, and a pretty poor support, so maybe try it but don't rely on it.
Roserade @ Black Sludge
Ability: Natural Cure
EVs: 252 HP / 240 SpD / 16 Spe
Calm Nature
- Leech Seed
- Toxic Spikes
- Sludge Bomb
- Giga Drain
There are many more good supports, but these are some of the most common and most used in any type of competitive battle.