from my experience so far, here are the most common leads:
Sticky Web: araquanid, ribombee, shuckle
Dual Screens/Veil: koko, klefki, zapdos, alolatales, froslass
Trick Room: uxie, carbink
Anti-Leads: greninja, aerodactyl (taunt), m-medicham, weavile (double priority)
Webs is hard checked by serp, which gains a +1 speed boost, effectively outspeeding everything bar unviable scarfers and possibly sweeping. Dual screens can be defogged away.
Then there's Trick Room. Maybe it's just me, but there are no good trick room checks. Either use a bunch of slow and/or bulky pokemon which isn't how hyper offense works, or stall out tr turns, or use priority, but none of them seem to be effective. And it seems like around 15-20% of teams are trick room which isn't a lot but definitely not insignificant.
edit: ribombee set (suicide lead):
Ribombee @ Focus Sash
Ability: Shield Dust
EVs: 4 Def / 252 SpA / 252 Spe
Timid Nature
IVs: 0 Atk
- Sticky Web
- Quiver Dance
- Moonblast
- Hidden Power [Fire]
Sets up webs and hopefully does some damage before fainting. 2nd and 3rd slots can be switched, but double attacking leads are rare so getting a QD boost seems better. HP ground can be run if heatran is an issue.
Beats most leads because of its 381 Spe, but loses to double priority and is rendered useless by prankster or faster taunt users.
Getting webs is really important especially for jirachi and kingdra, which can flinch and crit, respectively, the opponent to death without needing a speed boost. Scarfers are rare and generally unviable in this meta.