As Trivia Crack has not implemented advanced accessibility features in cards yet, I was looking for some communities or web sites where cards are explained with name and value.
I just googled some cards name, such as: Hector bonzo "trivia crack" cards, and found a reddit community, about Trivia Crack, where some of the cards names are explained with their correspondant values in coins, gems, lives, or spins.
I found it right now, so, I am not sure they are all documented with their correspondant bonus value, but it may be a good place to get in touch with other Trivia crack users - i cannot be sure Trivia crack owners write there. For trivia crack feedbacks I often use the @triviacrack twitter account.
I'll try to find out all cards and then create a guide, we may help each other with cards we own, to create the complete user guide, till Etermax releases the VoiceOver friendly cards feature. They said it publicly into Facebook trivia crack italian page so I have no reason to think they're lying publicly, it's matter of time.