I searched for 'Tukaram' and found no results. What should a devotee do when the text doesn't mention a saint they revere?

The text does not mention Tukaram, but it provides guidance for this exact situation by emphasizing the principle of 'Ye yatha mam' (As they approach me...), which is highlighted in Chapter 19. This puts the 'entire burden on one's actions.' The guidance is to take your reverence and turn it into practice. As an example from Chapter 19 describes, a devotee decided to chant the name of Rama and was immediately met with a song about Rama. This illustrates that when you begin to regulate good thoughts and surrender with an undivided heart, the Guru provides encouragement and confirms your resolve, making the specific name less important than the sincere devotion behind it.