Agreements related to wagers that are considered valid are known as?

Agreements related to wagers that are considered valid are known as collateral to wagering. This term refers to contracts that are legally enforceable and directly associated with betting activities. While wagering agreements themselves may be considered void or unenforceable in many jurisdictions due to public policy, collateral agreements can include arrangements that regulate the stakes or the terms under which the wager is made. Such agreements may be upheld by the courts since they do not promote the wagering activity itself but rather provide a legitimate framework in which the bet can be managed.

Understanding this context highlights why the other choices do not accurately capture the essence of valid agreements related to wagering. Collateral agreements, supportive contracts, and supplementary agreements do not specifically denote the legally viable nature of contracts that relate directly to wagers, which is why they are not the correct terms in this scenario.