Minecraft wiki entry for Explosive, associated text: TNT, an explosive block.
Minecart with TNT, an entity that is primarily detonated by activator rails.
End Crystal, an entity that explodes when hit.
Bed, explodes in the Nether and the End.
Respawn Anchor, explodes in the Overworld and the End if powered by glowstone.
Firework Rocket, bursts in midair.
Etho Slab, a joke block that spawns anvils when exploding.
Creeper, a mob that explodes if the player get too close.