MB3 99b: Purchasing Land in Israel on Shabbos (306:9-12)

Violating a d'rabbanan for a goseis on Shabbos. Giving collateral to a non-Jew on Shabbos. Buying land from a non-Jew in Eretz Yisrael on Shabbos. Announcing a lost/stolen item on Shabbos. Releasing a cherem on Shabbos.