a 'Tuple' like struct that can handle a polymorphic type ( but not have imutability ) at least, is a way of store random types of data at once.

tuple_like.odin

package tuples_like

import "core:fmt"

// Values :: union #no_nil {string, int, f32, bool} // for now, compile assertion error problem :: https://github.com/odin-lang/Odin/issues/1918

Poly :: struct {

  data : union { string, int, bool, f32 },
}

Tuple :: struct {
  ret : [dynamic]Poly,
}

main :: proc () {

  {
	  a : Tuple
	
	  append( &(a.ret), Poly { data = 42 } )
	  append( &(a.ret), Poly { data = 93.93 } )
	  append( &(a.ret), Poly { data = "Hi 5" } )
	  append( &(a.ret), Poly { data = true } )

	  fmt.println ( a )
  }
}

Odin version

odin version dev-2022-12:521ed286