Love this deck! There are a few cards I would suggest, firstly the mana base looks nice, but if your budget permits Verdant Catacombs would be ideal. I don't know how I feel about the Snow-Covered Swamp , as it really hurts to have a land that doesn't produce . Pendelhaven needs to go down to a one of in my opinion, though it is really awesome when you draw it making one want to play a playset, it is brutally painful when you have Haven1 and then draw Haven2. Inquisition of Kozilek is definitely a good reason to play in infect, and I feel that one card that matches well with it is Surgical Extraction , be it in the board or main deck, it allows you to target a fetchland in the opponents graveyard, look at their hand, and choose if you want to attack. If they have removal and you don't have an answer you don't have to attack, if the don't attack. Seeing you as semi-budget Surgical Extraction can be a bit expensive but it's on a down trend currently so I'd look at picking up a few copies soon.

Anyways, awesome deck, good luck brewing!

match_lighter: Thank you for your appreciation :)
For the manabase: the next plan is to go +2 Fetchlands, -1x Forest , -1x Snow-Covered Swamp . Since Forest and Overgrown Tomb are both fetchable with the "Forest"-keyword I can go for the budget version of Verdant Catacombs : Wooded Foothills / Windswept Heath .
The only reason to run Snow-Covered Swamp is against Blood Moon , which is not played very much, also i'd need a full playset of Verdant Catacombs to fetch is consistently. So neither my budget allows it nor have I the requirements by the Meta to play it.
(It allows me to play Inquisition of Kozilek and Plague Stinger , otherwise I would use the to animate Inkmoth Nexus ).
Regarding Pendelhaven : I upgraded to 2 last week and need to playtest. You increase the consistency of drawing it but also run the risk of beeing stuck with one on the field and one in hand. Need to see how the playtests go and then I'll decide if I go down to 1 again. 3 seems an overkill to me.
I never thought of using Surgical Extraction in such a matter, it seems like a good idea. Maybe I can borrow the card or proxy it for playtests, but currently it is out of my budget.