overflow indicators on folders with many elements

For folders with many items its impossible to see if there are more items than visible. Is it possible to add an optional indicator? suggestions:

1; add gradient. add a contrast gradient on the bottom if items are hidden. add gradient on top if items are hidden

2: add an arrow up/down if items are hidden. could ofc be any symbol. a dot is clean and if placed near top/bottom border informs well. if you are in the middle of the folder and it overflows both directions just show both indicators.

3: scroll bar. i personally am not a fan. but it does solve it....