I agree with the above that 78 is too many. If the deck is for fun then you don't need to change it but if you want to make it more consistent you want it at 60.
One of the first cuts I would make is remove
ponder. This will allow you to play it in sanctioned modern events.
Swiftfoot boots allows you to protect your creatures and active vorel at haste speed but i don't think you find yourself thinking "I wish i would draw
swiftfoot boots" very often
Invisible stalker doesn't go in tandem with the rest of the decks direction. It seems like a threat the is untouchable but doesn't pull in the same direction as the rest of the deck
Your aim is to draw lots of cards through +1/+1 counters, and make huge guys to swing in with. Because of this I do not think you are likely to deck yourself and there is probably no need for the elixer
Bioshift can be
dead if you have no creatures in hand, it seems like it is too tricky
I am unsure you require a sink for colourless mana that kruphix provides and if you keep casting your spells then 7 should be enough cards (you don't have a load of reactive cards that require you to keep a full grip)
Cards to consider:
Cold eye selki is a good fit
Into the roil offers you some interaction
orhan viper would be a great creature to pile counters onto
Obviously there are all the normal $20+ cards that would be good but I have tried to avoid these
Hope that is the kind of help you are looking for
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