Choice scarf pokes in general are good to lead with. Most use moves like U-turn or Volt switch, so they can easily switch to a counter or check, break a sash or something like it, and keep offensive pressure and momentum. On my current team, Landorus-T has been my go to when in doubt:
Landorus-T (M) @ Choice Scarf Trait: Intimidate
EVs: 28 HP / 252 Atk / 228 Spd
Naive Nature (+Spd, -SDef)
- Stone Edge
- Hidden Power [Ice]
Has U-turn for quick get away, strong 145 attack to scare things out, and very good at countering physical leads such as Tyranitar(thanks to intimidate), being able to damage him heavily with U-turn, or simply take him out of the match with earthquake, if he decides to stay in. By that logic, he would make a great lead for sun teams.
I try my best to be cheerful, no matter what. If you challenge me, I hope you do your best to be as well :).