There are no such adapters that would allow 8mm, Hi8 and Mini DV tapes to be played in a VHS VCR. Only the old VHS-C tapes can fit and play in an adapter.
There are several reasons why 8mm (or Hi8 and miniDV tapes) cannot be physically played in a VHS VCR:
1. 8mm (Hi8, miniDV) is a different format with different technical characteristics than VHS. These formats were never developed with the intention to be mechanically compatible with current VHS technology.
2. 8mm/Hi8 tapes are 8mm wide (miniDV is 6mm wide), while VHS tape is 1/2" wide, making it impossible for a VHS video head to read the taped information correctly.
3. 8mm/Hi8/miniDV tapes are recorded and played at different speeds than VHS, so even if the tapes could physically fit into a standard VHS VCR, the VCR still couldn't play back the tapes at their correct speeds.
4. 8mm/Hi8/minDV audio is recorded differently than VHS. 8mm/Hi8 audio is recorded in AFM HiFi mode, while miniDV audio is recording in 12-Bit or 16-Bit PCM digital audio format. So, even if the video could be played back in a VHS VCR, the audio could not be read properly.
5. 8mm/Hi8 video is of higher resolution than VHS and is recorded in a different bandwidth length (miniDV video is recorded digitally), so once again, a standard VCR still could not read the information correctly, even if the tape could fit into a VCR.