The most common verb(well it is not really verb, it's a copula) is desu (です). です is used to for more polite speech. Often です is translated to am, are, or is in English. Example for marii desu (マリーです。)which is could be translated as "I am Mary.", or "This is Mary." depending on the context.
Also, there is a less polite form of です, which is da (だ). Unlike です, だ can be completely dropped. Example for, genki(元気。) which can mean "I am well." You could also use genki da (元気だ。), but 元気 sounds more natural.