It is recommended to use either a penetrating sealer or an epoxy system on a garage floor. A penetrating sealer like the Siloxa-Tek 8505 or the Siloxa-Tek 8510 is best if you are looking for natural finish. The major difference between the two products is that the Siloxa-tek 8505 is water based and the Siloxa-Tek 8510 is solvent based. The Siloxa-Tek products will resist degradating deicing salt damages to reduce cracking and spalling and they will resist exposure to grease and oils.
If you are looking for more of a coating or decorative finish a better choice would be an epoxy system. An epoxy system consists of an epoxy basecoat like the Epoxy 325 and a topcoat like the Urethane 645. Penetrating sealers and epoxy systems are popular concrete sealers for a garage.