Regular phone call - At the very least calling your little or big once a week.
Writing letters or drawing pictures
Take a picture and email or text it after write the letter
Mail - bigs for sure could, but littles might need to send the letter back a different way.
Helping with homework over the phone.
Watch the same tv series or movie - age appropriate - and talk about it on the phone, (or video call), or watch it at the same time or text throughout it.
Drop off a bag with supplies to make dinner at the same time from each of your homes while on speakerphone or facetime/video calling.
Start a book that you take turns reading on speaker phone or if you have a younger little, maybe you could just call or video chat to read the book to them.
Maybe they are reading something for school and bigs could read it too.
Draw a simple picture and describe it to the other person - then take a picture, send it to each other and see if they look the same.
Scavenger hunts from each others homes - a shared list and race to see how fast you can do it.
Video Phone Call
Facetime
Zoom Meeting - Bigs if you would be more comfortable, this may give you a record option.
Google Hangouts - most schools are utilizing google, so you can send a chat invite and that will also allow you to have video calls or regular audio calls as well.
Tell us if you need help setting this up because we can even set the meeting up and then leave.
Email - share email addresses and make sure they work - some schools restrict outside school mail
Helping with homework
Using Zoom, Hangouts, or other video calls - some let you share your screen and you could watch a movie together using Netflix or Amazon or Hulu and talk to each other while you watch.
Order a pizza for the little and you and Facetime while you eat.
Read the same book with online resources - if you need help finding a book, let us know. Get on a call in some way and talk about the book. Books - will probably be digital unless you have two copies.
Create a Facebook group of just the two of you so you can host your own events and watch parties.
If you and your little both have iPhones or can download a list and picture sharing app, you can make a scavenger hunt and try to find the items on a shared list.