Tips for Basic Filler Metal selection along with some resources for filler metal selection.
Aluminum filler metal chart from Aloctech http://alcotec.com/us/en/support/upload/Aluminum_Filler_Alloy_Selection_Chart.pdf
Washington Alloys Stainless Filler metal chart https://washingtonalloy.com/wp-content/uploads/2020/12/stainless-selector-guide.pdf