All the Online Tests You Could Ever Want
This website has a number of autism assessments from Short Autism Quotient to Executive Skills Questionnaire and everything in between including some for ADHD.
There's also The Adult Autism Spectrum Quotient (AQ) on Autism Canada's website here
And still more online tests here https://www.autism360.com/autism-test-online/
Please note THESE TESTS ARE PURELY INDICATIVE IN NATURE AND MUST NOT BE CONSIDERED A DEFINITIVE DIAGNOSIS OF AUTISM.