Using it on something with Mold Breaker? It just wouldn't work period, so that probably doesn't count..
Hustle? Most (All?) pokemon to learn Trace use Special Attacks, so boosting Attack and losing accuracy wouldn't be good :|
If a porygon has signal beam, swarm can kinda be useful.Tracing Stall, Color Change, Iron Fist, Plus, Minus, Reckless, Skill Link, Swarm, and Illuminate won't help much either.
Using it on something with Mold Breaker? It just wouldn't work period, so that probably doesn't count..
Hustle? Most (All?) pokemon to learn Trace use Special Attacks, so boosting Attack and losing accuracy wouldn't be good :|
Gallade actually learns Trace.