The options for Starter Decks are Amethyst and Amber, Emerald and Ruby, or Sapphire and Steel
Dig Through Time This is a Delve-powered card selection, and clearly one of the best blue cards MTG has ever designed for finding exactly what you need
As usual, the Azurite Sea expansion has release dates for both smaller local stores and one for the larger mass market retailers
The biggest problem with it is being in both white and blue really restricts the amount of decks it can go in, and since you're in blue you likely have better draw engines
Some decks rely on the devotion mechanic, with Master of Waves, Thassa, God of the Sea, and Thassa, Deep-Dwelling offering good payoffs for having many blue symbols around
You can drop it early enough to matter