Quantum (QRL) is another crypto project that has recently successfully forked to the RandomX algorithm, the project initially launched with CryptoNight algorithm. Now with the fork to RandomX mining QRL is viable only with CPUs as although there are GPU miners available, the performance of CPU mining of RandomX, especially with the latest AMD Ryzen processors is significantly better in terms of performance and efficiency compared to GPUs. Of course the latest hardfork brings some additional new features to the Quantum project besides the switch to the RandomX algorithm that you might want to check out as well if interested. There are a number of RandomX miners out there available for you to use for mining Quantum such as XMRig, SRBMiner-Multi and XMR-STAK-RX. If you are looking for an exchange where you can trade QRL, then Bittrex is probably the one to go for, although it might not have the largest trading volume.