+1! The deck is beautiful!

Some suggestions:

• High Market, Phyrexian Tower - extra sacrifice outlets, the Tower especially good, because it provides speed. I understand that you already have a decent sacrifice outlet in commander zone, but it always good to have another one in reserve.
• Reflecting Pool
• I guess you avoid using Sensei's Divining Top because you have Library in the deck? I would recommend to use it even if that's the reason.
• Night's Whisper, Sign in Blood- decent draw spells for not running out of gas.

Hope it was helpful! I wish you good luck in making Varolz even more dangerous! :)

Hey Matrixxx999, great to see someone taking interest in card choices! I'll run over my reasonings for my exclusion of those card choices real quick, and I'll add them to the notable exclusions as well.

High Market, Phyrexian Tower: These look good at first glance, but there are some major downsides; first, for high market, it doesn't produce coloured mana, which you really want in this deck, and it's not actually that great of a sac outlet, only being a once-per-turn and giving nothing in return, I'd much rather be playing a coloured source in it's place. Second, for tower, I would totally run the card, if only it produced coloured mana without having to sacrifice a creature. Again, you really want coloured mana, and typically, you're only going to have 1 non-Varolz creature at a time, which you need to bank for pattern of rebirth and natural order, otherwise they become dead cards.

Reflecting Pool: I don't really need this in a 2-c deck, I'd rather play a basic, and have more resilience against blood moon

Sensei's Divining Top: Actually a bit slow for the deck, if you're going turn 1 dork -> turn 2 varolz, it doesn't afford you much time or mana to actually use it efficiently, it does smooth out every turn after those, but those are going to be the key turns when you're looking to have action in your mulligans

Night's Whisper, Sign in Blood: I actually highly suggest both of these for potential budget builds or more midrange builds, but because this is a budgetless build, I'd much rather be playing higher-powered draw like ad naus or necropotence, or just be playing tutors instead. You are also looking to win before running out of gas becomes an issue generally, so they're not as good here as they are in a Doomsday deck, because they can't serve the dual-purpose of cracking a pile.

Hope I cleared up those card decisions a bit!

You explained everything very clearly, I got you're point. Your opinion was useful for me too, so thanks.