• Basic forms
• 来る（くる）— to come / base form
• 来ます（きます）— polite / I come / masu form
• 来た（きた）— past / came / ta form
• 来て（きて）— te-form / come (and …) / linking or request
• 来ない（こない）— negative / don’t come / negative form
• 来れば（くれば）— if (someone) comes / conditional
• 来い（こい）— come! / imperative
• Other common forms
• 来たい（きたい）— want to come / 〜たい form
• 来られる（こられる）— can come / be able to come / potential
• 来なかった（こなかった）— didn’t come / past negative
• More
• 来よう（こよう）— let’s come / 〜よう form
• 来ている（きている）— coming / has come / progressive / state

来る (くる) is an irregular verb — one of only two major irregular verbs in Japanese (the other is する). Its stem changes between く, き, こ depending on the form. Common examples include: 友だちが来る — “A friend comes.” 明日来てください — “Please come tomorrow.”