Try the free app Bitsboard.

Visit http://www.do2learn.com

Have a look at the resources on: https://www.speechandlanguagekids.com/free-materials/

Colourful Semantics have a wealth of resources for free to support early language and sentence construction: https://integratedtreatmentservices.co.uk/our-approaches/speech-therapy-approaches/colourful-semantics-2/

The Communication Trust has many links to different resources for parents as well as schools (some free) as well as offering some free training which is very interesting: https://www.thecommunicationtrust.org.uk/