A blue progress bar (customisable) that counts from last mob hit so you can time your leash on a mob for kiting/escaping, if you can see the mobs level, it displays the estimated leash time for that mob when running in a straight line (if the mob is too high level, it defaults to max leash timer). It's not perfect but gives you an idea, couldn't find what I wanted so threw this together. Also attempts to reset leash if a slowdown is detected and you are re-hit by the mob(s), Guideline level is also set if you walk by a mob and aggro it, nameplates need to be on for this feature, it scans local mobs and takes the highest level for the leash estimate if available.
Estimated Leash Guidelines:
1-29: ~11 sec
30-39: ~12 sec
40-44: ~13 sec
45-49: ~14 sec
50-60: ~15 sec
Made with "Combat Timer" by blasteh as base, I use both together as pictured above it in the image. Above that is "Target Mob XP" by Urbit. See version 1.0.9 for text only version.