Quote Originally Posted by E’Tallitnics View Post
A17: Yes, but only with a Shadow Blade. The text of Sneak Attack reads, in part, "The attack must use a finesse or a ranged weapon." Shadow Blade is a simple melee weapon and has the finesse property.
R17: Addendum. Booming Blade (and Green-flame Blade) will also allow Sneak Attack if you use a finesse weapon with them. The Booming Blade Cantrip, which in its description says "As part of the action used to cast this spell, you must make a melee attack with a weapon against one creature within the spell's range, otherwise the spell fails." So if your weapon is finesse already, then that would count to trigger sneak attack, assuming the other conditions (either advantage, ally within 5ft, etc) are satisfied.

You can also Sneak Attack OFF of your turn with a cantrip with opportunity attacks if you have the feat "War Caster" (which you can satisfy the prerequisite of being able to cast a spell through racials, Magic Initiate, multiclass, Arcane trickster, or a few other feats), because one of the benefits is "When a hostile creature's movement provokes an opportunity attack from you. you can use your reaction to cast a spell at the creature, rather than making an opportunity attack. The spell must have a casting time of 1 action and must target only that creature." Booming Blade definitely counts. Green-flame blade may count, but the jumping to others may make the DM say "no" because it "kind of" targets more than one creature (I'd rule OK, but others may not).