Learn Russian: Вам нужно подобрать туфли, которые будут сочетаться с любым платьем. - You need to pick out shoes that will go well with any dress.

While выбрать just means to choose or select, подобрать means to select something so that it matches or fits a specific requirement. Here, the shoes need to be selected specifically to match the dresses, making подобрать the most accurate choice.

What case does the verb сочетаться require?

The verb сочетаться (to go well together, to combine) requires the preposition с (with) followed by the Instrumental case. In this sentence, that gives us с любым платьем.

Why is the future tense будут сочетаться imperfective, when the first verb подобрать is perfective?

The act of picking out the shoes is a single, completed action, so подобрать is perfective. However, the shoes matching the dresses is an ongoing, continuous state that will be true whenever they are worn. Therefore, the imperfective future будут сочетаться is used.

Could I use всяким instead of любым here to mean 'any dress'?

Using любым is much better here because it emphasizes free choice: 'any dress you happen to pick.' The word всяким leans more towards 'every kind of' or 'all sorts of,' which sounds a bit less natural when talking about picking an outfit for a given day.