So, at the moment, there is no way to receive catalyst for any of these weapons: 1. Graviton Lance 2. Sunshot 3. Sweet Business I've googled for some time on this question, the answer is "catalyst can be obtained through Faction Rally". Faction Rally was not available on season 4 and still not available on season 5. I kindly ask moderators and support team to help me and the community to figure out ways to obtain catalysts or revisit the problem. Have a good day!