Signup Genius is a great online tool where people can sign up for time slots. I think this would be perfect for scheduling Parent-Teacher Conferences. I can control what times are available and parents can choose which time works best for them. I receive an email alert each time someone selects a time slot or cancels. Participates are also able to go back and make changes to their selection if necessary.
Remind is a great communication tool. Participates must be 13 years or older so I use this tool with parents only. Parents sign up with a code specific to the "class" you have created. They can do this in couple of ways but the easiest is to text the code to a specific number. They will receive a message back asking for their full name and if they are a parent or student. They respond and are signed up! It's that easy! The great thing about this tool is that not all parents check emails or have email but they all have a cell phone. This tool send your messages to their cell phone as a text message but since it goes through the app no one sees your phone number. You can send whole class announcements, group messages or contact and individual person.
This tool is great for white noise. I have a couple of students with ADHD and ADD that I would recommend this app for. They would like being able to pick their own sounds to listen to while completing work and it would help them tune out other distractions that may be going on around them. Noisli could also work great for the whole class to help create a relaxing work environment.