This is simply an initial try-everything list, but it should quickly become clear what cards do and dont perform in these shells
If creatures are that much more valuable than spells in your list then these are pretty good options

Rarity: M Cost: 1R // 2URW Pow/Tgh: 2/1 Card Type: Legendary Creature - Human Performer Hero // Legendary Creature - Spider Human Hero Name: Gwen Stacy // Ghost-Spider Finish: Regular Card Number: 209 Set Name: Marvel's Spider-Man Related Products Spider-Bot Marvel: Spider-Man - 41/42 NM-Mint, English 12 In Stock NM-Mint, English 12 In Stock NM-Mint, English 12 In Stock Hot Dog Cart Marvel: Spider-Man - 41/42 NM-Mint, English 11 In Stock NM-Mint, English 11 In Stock NM-Mint, English 11 In Stock Prison Break - Foil Marvel: Spider-Man - 41/42 NM-Mint, English 1 In Stock NM-Mint, English 1 In Stock NM-Mint, English 1 In Stock Grow Extra Arms Marvel: Spider-Man - 41/42 NM-Mint, English 12 In Stock NM-Mint, English 12 In Stock NM-Mint, English 12 In Stock Biorganic Carapace - Foil - Prerelease Promo Marvel: Spider-Man - 41/42 NM-Mint, English 2 In Stock NM-Mint, English 2 In Stock NM-Mint, English 2 In Stock Thwip

Having lots of lands that can produce two or more colors will help avoid these types of scenarios
The Ur-Dragon feels like having a Sol Ring emblem sometimes, and the creature itself is a massive card advantage engine if it ever hits the board