OP_CHECKWILDCARDSIGVERIFY or "Wildcard Inputs" or "Coalescing Transactions"

Though technically it promotes address reuse, it is still considered safe as the coalescing transaction should be deep enough in the blockchain to avoid re-org tomfoolery by the time the wallet user wants to spend funds from the address. The proposal was discussed on the Bitcoin-dev mailing list, where some issues were raised. One such issue is that the basic form of this encourages address reuse unless the wildcard can be constructed in a way that it matches a whole branch of an HD wallet. Another issue is the danger of reorgs, which can be addressed by including a block height indicating the maximum block that any UTXO can match and adding a minimum block height to prevent unnecessary scanning. Despite these concerns, the coalescing transaction is seen as a nice way to reduce the UTXO set.