We're going to do a thorough analysis of each deck, highlighting its goals and how well it accomplishes them, check out its deckbuilding fundamentals, identify its strongest and weakest cards, then use all that information to create a high-impact list of upgrades for under $30
Tribal Reanimator Commanders (Scion of the Ur-Dragon, Horde of Notions, Gisa and Geralf, Kaalia of the Vast, etc.) There are a LOT of commanders well suited to tribal reanimator strategies, but the 4 I have listed here exemplify what you should be looking for when narrowing down which legendary creature should be at the helm
1 Foil-Etched Legendary card + 99 nonfoil cards
In your developing turns, the flash on it offers you an amazing level of flexibility, letting you waste your opponents mana by not letting them use removal on your turn, catching your opponent off-guard sometimes (especially if they dont realise youre on Mono-Blue), and letting you hold up countermagic whilst still threatening to develop your battlefield if you dont need to counter something