Application for EMDR therapists with light and/or sound options. No adds. Free.
There is also option to run this app controlling Arduino based EMDR machine. Description of Arduino/hardware part is here
https://www.element14.com/community/community/design-challenges/design-for-a-cause-2021/blog/2021/03/16/open-source-emdr-machine-1-initial-plan

NOTE: do not use it unless you are EMDR therapist!