The phrase "choose up" is commonly used in informal settings to refer to the act of selecting a team or partner for an activity or game. However, there are numerous synonyms that can be used to express this idea, such as "pick," "select," "decide on," "opt for," "plump for," "go for," "settle on," and "take up." Each of these words carries a slightly different connotation, from the deliberate and decisive "decide on" to the more spontaneous and adventurous "go for." The choice of synonym often depends on the context and tone of the conversation, but any of these options can be used to convey the same essential meaning.