Jolteon + Spikes: This is a good theorymon as it gives the tier a good spiker with amazing speed and offensive presence alongside giving jolteon a niche over other electric types. Heck it can even run a suicide lead set like azelf and normal aerodactyl do without taunt but access to spikes for more hyper offensive teams. A simple set of spikes volt switch hidden power ice shadow ball gives it enough coverage to work with and provides volt turn teams spikes support that doesn't drain momentum and a volt switcher in one package. Maybe a mega beedrill + jolteon core?
Donphan + Fairy-typing: I like this one. It gives elephant of lame an amazing niche over hippo as it now is immune to dragon and resists fighting, dark, and bug, it has a secondary stab, and the ability to run a rock polish set. With it's new typing it can also counter any dragon dance mega tyranitar without ice punch which is another good aspect as not many teams are prepared for it. Did I menton it's a stealth rocker that can beat mega sableye? I might work on some cores for this such as ferrothorn + donphan since both have reasonable defensive synergy and can blanket check many meta game threats. While it's typing leaves it weak to common types the advantages of it more then make up for it.
Sylveon + Geomancy: I can see why people think it's broken but one thing about sylveon that makes me think it's probably not that broken is it's terrible offensive movepool. It has no coverage for steels outside of hidden power and only has psyshock and shadow ball as other special moves so no matter what hidden power it picks it is walled by something. It's speed after a geomancy is only so fast in that any scarfer with a strong physical stab on it that's not resisted can pretty much wipe it out since it has shit physical bulk. Another thing about it is it only gets one shot to set up. Finally it can't switch into knock off like other fairies can since removing the power herb means you might as well sack it.
Infernape + Unburden: This is the worst of the bunch because exactly what does it do with it? It has to run a one time boost item which isn't good because infernape isn't that strong without a boosting item and it lacks ways of activating it. Besides even if infernape somehow pulls off unburden it's easy to revenge kill due to lacking enough firepower to KO stuff without a boosting item and it's bad bulk.
Donphan + Fairy-typing: I like this one. It gives elephant of lame an amazing niche over hippo as it now is immune to dragon and resists fighting, dark, and bug, it has a secondary stab, and the ability to run a rock polish set. With it's new typing it can also counter any dragon dance mega tyranitar without ice punch which is another good aspect as not many teams are prepared for it. Did I menton it's a stealth rocker that can beat mega sableye? I might work on some cores for this such as ferrothorn + donphan since both have reasonable defensive synergy and can blanket check many meta game threats. While it's typing leaves it weak to common types the advantages of it more then make up for it.
4 Atk Donphan Play Rough vs. 248 HP / 124+ Def Mega Sableye: 156-186 (51.4 - 61.3%) -- guaranteed 2HKO
Sylveon + Geomancy: I can see why people think it's broken but one thing about sylveon that makes me think it's probably not that broken is it's terrible offensive movepool. It has no coverage for steels outside of hidden power and only has psyshock and shadow ball as other special moves so no matter what hidden power it picks it is walled by something. It's speed after a geomancy is only so fast in that any scarfer with a strong physical stab on it that's not resisted can pretty much wipe it out since it has shit physical bulk. Another thing about it is it only gets one shot to set up. Finally it can't switch into knock off like other fairies can since removing the power herb means you might as well sack it.
Infernape + Unburden: This is the worst of the bunch because exactly what does it do with it? It has to run a one time boost item which isn't good because infernape isn't that strong without a boosting item and it lacks ways of activating it. Besides even if infernape somehow pulls off unburden it's easy to revenge kill due to lacking enough firepower to KO stuff without a boosting item and it's bad bulk.