Simple games to use in class:
1. Information gap: each student has a picture. One describes it, whereas the second student draws it. Then, switch roles. Good for practicing words related to appearance and clothes (freckles, necklace, etc.) and location (over, under, below, above, etc.)
2. What has changed? Could be done with two pictures with some differences or with some realia on the table or in the classroom. Good for practicing the Present Perfect tense (with realia) or the Present and Past Continuous tenses (with static pictures where somebody is running, something is sneezing, etc.).
3. Style watch: create a style description for one of the school teachers or just famous people. What do they wear? What do they like? To make things more interesting, while presenting, do not name the person right away. Instead, let everyone guess who the person is from the description.
4. Pictionary: draw something and ask others to guess the word. Good for any vocabulary.
5. Hangman: quite a common game to lead to some topic as a warm-up. Give a number of letters in the word and ask students to guess the word letter by letter.
6. Questions and answers: bring some pieces of paper and ask each student to write 1-3 questions. Shuffle them and give to random students to answer.
7. Collective writing (could also be done with poems): as soon as one student writes one line of the poem or one sentence of the text (one paragraph for longer assignments), pass the paper to the next person in the circle and continue writing. This trains cohesion in writing.
8. Four corners game: students stand up and hear some statements. If they agree, they go to the first corner. If they disagree, they go to the second corner. If they don't know, it's the third corner. If they don't understand what the teacher said, they choose the fourth corner. When you teach something online, I imagine that it's possible to use Kahoot for a similar survey, with students choosing one of four answers on their mobile devices.
9. Finish the sentence. It's a good game for something like the Present Perfect tense when you start the sentence like "Never have I ever..." (this particular sentence is also used for a drinking game in the U.S.!) or "I have never eaten...", "I have never been to...". Good for the first lessons with a group of students because it's a way to learn about them more.
10. Category game. Just a fun vocabulary game when you have to think up as many words starting with the same letter as possible in one minute. Yeah, these words have to represent different categories, e.g. a name, a piece of clothing, a musical instrument, a country, etc.
I like these games a lot because very few of them really need any preparation or handouts. They are perfect for a lazy teacher. Usually, I enjoy all of them if something goes wrong or not exactly as I planned or if there's some time left, but everyone is too tired for a "serious" grammar/vocabulary presentation or practice.