Against Dredge, those cards are Stinkweed Imp and Conflagrate
Six mana is a lot to nab a creature that the Crystal has exiled, but there are few times where doing so will be a bad thing
If adding a single red mana one time for free is too good for Modern, then cards that repeatedly offer free mana (Chrome Mox, Eye of Ugin, and Mox Opal) or offer a one-time burst of more than one mana (Seething Song and Summer Bloom, which was primarily used as a ritual with bounce lands in Amulet of Vigor decks) are too good as well
Charizard 25/185 - Vivid Voltage The Pokmon Company Pokmon Stage 2 - Evolves from Charmeleon 170 HP Once during your turn, you may look at the top 3 cards of your deck and put 1 of them into your hand
Serialized Doctor cards appear in this slot
The best approach is treating cards as a small percentage of a broader financial plan, not the plan itself