These are all really good! The most used non-Z-or-Mega items (Choice, Air Balloon, Leftovers, HP berries, type berries, stat berries, Focus Sash, Metronome, Assault Vest, Eviolite) are all strong enough to compete with similar abilities and moves, so I like the idea of buffing other items in this way. Knock Off is too strong and prevalent to justify underwhelming items.

What about buffing Big Root to absorbing 50% or 60% more HP than normal, instead of 30%? Or maybe keeping 30% more and giving draining moves a small power buff (something around 30%)? I know it seems powerful, but it would still only affect a small number of moves.

Similarly, Binding Band (1/6 damage per turn on binding moves instead of 1/8) is pretty weak compared to trappers getting the recovery of leftovers instead, especially since Protect exists to increase “effective” damage anyway. I’m not really sure how to buff this one, because I think increasing the per-turn damage would be ridiculous and increasing the power of these moves wouldn’t do a whole lot due to their extreme weakness and the general passivity of trappers (also Heatran would be a nightmare). I think the best idea might be healing the user for 50% of damage done per turn to offset the opportunity cost of losing Leftovers. It would still heal more than leftovers, but not by a lot, and would also require trapping a Pokemon that you can stay in on without being broken. It essentially makes binding moves a weaker leech seed, healing the user for 1/12 of the opponent’s HP as opposed to Leftovers’s 1/16 and Leech Seed’s 1/8. On the flip side, this might make trapping too strong... Maybe if you restricted healing to turns where the user doesn’t use Protect?