daring cedar
https://www.moxfield.com/decks/o7nl3MxbAUOhY0R_LhmPDQ
My wife wants an poison counter deck, and I'm trying to keep the deck budget unless I already own the card. I feel like the deck needs more ramp, but I don't know what to cut. I also need help making the mana base a bit better, as a 4 color deck is rough on a budget at this price point.
daring cedar
bump
tranquil igloo
i would cut crawling chorus, phyrexian censor, virulent
for draw you could include phyrexian arena or ripples of undeath. If on ramp i would probably recommend throwing in an everflowing chalice as you can proliferate the counters on it, glistening sphere could be good as well. I do like staff of compleation for flexibility, tho paying 2 for 1 mana might be abit costly
For manabase, not sure what to suggest personally. I run more budget and more basics, so I tend to use the "comes in untapped unless you control 2 or more", but I also run ixhel, so 3 vs 4 colors
those are my small suggestions
viscid harbor
I might recommend [[rigo streetwise mentor]] over fathom mage? You only have one way to add counters to it (revitalizing repast) outside of getting it to evolve and then start proliferating. I'm always wary of draw engines that are both obviously scary to opponents and incredibly vulnerable like the Fathom Mage's 1/1 stats.
On the otherside, Rigo can trigger off of a wide range of creatures, costs less, comes in with a shield counter which makes it less likely he takes a stray bullet and dies, and can become a pseudo-indestructible creature if proliferated enough times.
grand shadowBOT
daring cedar
i would cut crawling chorus, phyrexian censor, virulent
for draw you could incl...
Phrexian arena is pretty slow nowadays, I can give it a shot but since infect players usually get targeted I'd assume I'd want something that can get her at least a draw the turn she plays it.
tranquil igloo
the other one i mentioned is pretty good
you can pick 1 out 3 cards if you want
[[ ripples of undeath]]
grand shadowBOT
Enchantment
At the beginning of your first main phase, mill three cards. Then you may pay 
and 3 life. If you do, put a card from among those cards into your hand.
As the monster lay dying, it stared into the eyes of the human who slew it. Decades later, it has yet to break its gaze.
daring cedar
It still doesn't draw anything until the next turn, but at least it's cheaper and you get to look at more cards. I might go for that one instead
tranquil igloo
wdym net turn
you mill 3, pay 1 and 3 life and put something youd want into your hand
if not you just milled 3
daring cedar
You can only play it during your main phase, and it doesn't trigger until your next turn's main phase
Inless you're flashing it in somehow, but then that would be the same case as phyrexian arena
tranquil igloo
i guess sure
daring cedar
I might recommend [[rigo streetwise mentor]] over fathom mage? You only have one...
Yeah but there are 17 different creatures that can trigger evolve, and I can get multiple draws per turn. Rigo I'll need to have a spare 1 power creature to attack with, and it will likely die meaning I'll need more to draw more cards. Maybe if I were making a bunch of tokens, but idk about him in this deck. Plus I only have 11 1 power creatures, and only three of them can attack each turn without worrying about being killed by blockers.
viscid harbor
Sure, Fathom Mage can definitely be a powerful card and I don't think it's wrong to play it. I will point out that Rigo can also draw multiple cards per turn (one per player and per planeswalker you attack). My recommendation would be to play the card that appeals to you, but also to pay attention to how often it gets removed. And if it's getting targeted down frequently, then maybe it makes sense to choose the slightly more defensive option of Rigo, even if it doesn't have as high of a card draw ceiling.