Sequential-anytime valid inference refers to methods that guarantee anytime validity and type I error control even with infinite looks. It is entrenched in Markov's and Ville's inequalities and comes from game theory. Major companies use it (Netflix included).
An e-value is the payoff of a $1 bet against the null. Formally: E ≥ 0 with E[E] ≤ 1 if the null is true. Big E = the null lost money = evidence against it. Bonus: e-values multiply across studies and stay valid even if you peek and stop early. The p-value can't do that.