There's something in Gardevoir's moveset that I think may be somewhat underrated: Future Sight. Future Wish and Doom Desire are the two strongest attacks of their respective types, and cannot be blocked by Protect or any similar move (including Chesnaught's signature Spiky Shield and Aegislash's signature King's Shield). Thus...
Mega Gardevoir (Future Sight Offensive Support)
Ability: Trace (Pixilate)
IVs: 4 HP / 252 SpAtk / 252 Spd
Nature: Timid / Modest
Item: Gardervoirite
- Future Sight
- Moonblast
- Focus Blast / Shadow Ball
- Wish / Will-o-wisp / Healing Wish
Nothing will really feel comfortable taking a STAB 120 BP attack coming off of 165 base Special Attack unless it's resisted or immune. However, this set is designed not only to take out such checks, but to force the opponent into a rather uncomfortable position and soften things for its teammates to clean up later. Dark-types will eat a super-effective STAB Moonblast from the aforementioned monstrous Special Attack stat, and Steel-types will not enjoy a Focus Blast. Shadow Ball is slashed as an option to hit opposing Psychic-types for super effective damage as well as hitting Aegislash, which it would not be able to touch otherwise. The last moveslot is mostly filler, but the first two options slashed improve Gardevoir's ability to take hits and support the team. The Future Sight / Wish combo allows Gardevoir to act as a good pivot and gives it some form of recovery, whereas Will-o-wisp cripples physical attackers that try to prey on its lower defensive stat. Teammates that can use the Future Sight incoming to its advantage really make it shine, such as Fighting-types that can decimate the Dark- and Steel- types that try to negate the hit. For this reason, Healing Wish is also slashed as an option in the last slot, fully charging up a weakened teammate to come in and use that final Future Sight to its advantage.