Alphas/Betas for games. Most TOS's/EULA's for the beta say that the beta discs can't be sold/given away, during the beta or after the beta has expired. Depends on the terms of the EULA/TOS for the beta, though if planning to sell/trade them on CAG, please provide a copy of the EULA/TOS that explains they can be sold. Without that proof, betas can't be sold.
https://www.cheapassgamer.com/topic/49710-tradingfeedback-rulesguidelines-all-cags-must-read-updated-10212015/
https://www.cheapassgamer.com/topic/49710-tradingfeedback-rulesguidelines-all-cags-must-read-updated-10212015/