Each tapped creature contributes either one generic mana or one mana of its color toward the spell's total cost
Casting Sign in Blood every turn is excellent card advantage, even if it gets a little costly
Some fans are hopeful that Wizards will overturn the rules committee's controversial choice to ban Mana Crypt, Dockside Extortionist, and Jeweled Lotus, and we even saw the price of those cards recover somewhat after the initial crash
Tyvar the Bellicose As a strong competitor or even substitute for Lathril, Blade of the Elves, we have Tyvar the Bellicose
Note that tutoring from an opponents deck is inherently riskier than looking through your own cards, as you arent going to have perfect knowledge of what your options are before casting your tutor spell, and may not be able to retrieve the specific card you want
Not really worthwhile as a frog typal option, though