MAKECOMBO
Function: Returns combination of two arrays
=LAMBDA(array1,array2,LET(a,array1,b,array2,La,COUNTA(a),Lb,COUNTA(b),MAKEARRAY(La*Lb,2,LAMBDA(r,c,IF(c=1,INDEX(a,INT((r-1)/Lb)+1),INDEX(b,MOD(r-1,Lb)+1))))))
Here is example (attached image)
This is my first lambda function posted here...