When I was with Verizon, their "Message+" text messaging app had a feature where you could schedule a message to send at a particular time.

You would get to it by going to the contact, clicking the three little dots at the top, and clicking schedule message, then you just type what you want to say, choose when you want the message to be sent & then click the send button and it will send it when you choose.

Textra really needs this feature as it is a HUGE convenience for those that have to send regular messages to the same person and yet have memory problems.