Butt-Toning Exercises?

Single leg glute bridge, hip thrust on a Swiss ball with a barbell on your hips, single leg Romanian deadlifts, goblet squats, walking lunges, step ups, kettlebell swings, warrior iii. Use enough weight so that it's challenging to finish 8-12 reps. Then do 3-5 sets or 3-5 sets each leg. Seriously use challenging weights. Hip thrusters activate your glutes more than any other exercise.

Any exercise where you flex your hip then lock it out standing up will involve the glutes.

You can't "tone" muscles, you can either grow them or let them shrink by not training them. If you want it to look more defined you can do that by either growing it or lose overall body fat.

My favourite two exercises:

Squats - by going below parallel and squeezing your glutes.
Rack pulls - squeezing your glutes on lockout.

Deadlifts. Regular and straight leg.