Help me pair my socks
Perl 6, 46 bytes



{.kv.map(*=&gt;*+&gt;1),.keys.grep:{.{$^k}%2}}o*.Bag


Try it online!

Explanation

{                                      }o*.Bag  # Convert to Bag and feed into block
                 ,  # 2-element list
 .kv  # Key-value list (key is sock type, value is count)
    .map(       )  # Map to
         *=&gt;*+&gt;1   # Pair of sock type and count right-shifted by 1
                  .keys  # Keys (sock types)
                       .grep:  # Filter
                             {.{$^k}%2}  # Count is odd