None? Thyroxine rightly used has no side effects. Metformin is generally well-tolerated but may make you feel strange; i'm told no 2 people have the same effects. Coumadin (warfarin) may make you bruise more easily and you should avoid tackle football, but if you bloodwork stays good, you will probably experience no side effects. Glad you're proactive about your health.
Minimal if any. Agree withdr friedlander, also add that if you have taken metformin for more than 4 weeks and haven't had any disconcerting symptoms, it is unlikely to cause you any problems. Most common side effect from metformin is loose stools, but that goes away after the first few weeks, if it happens at all. Thyroxine, at the correct dose, rarely causes any side effects.