Here's my take:
[S-TIER - Kiki Kyutoryu]
Asura Bakkei: Moja no Tawamure | Asura: Ichibugin | Asura: Makyusen
[A-TIER]
Santoryu Ogi: Ichidai Sanzen Daisen Sekai | Ittoryu: Hiryu Kaen | Santoryu: Kokoba Madara Gari | Nitoryu: Gokuraku Anyo Rashomon | Ittoryu Iai: Shi Shishi Sonson | Santoryu: Kokujo O Tatsu Maki
[B-TIER]
Santoryu Ogi: Sanzen Sekai | Santoryu: Akaoni Okomega | Santoryu: 1080 Pound Ho | Santoryu: Rengoku Oni Giri | Santoryu Ogi: Rokudo no Tsuji | Ittoryu: Daishinkan | Ichi Gorilla Ni Gorilla Santoryu: Nigori-Zake
[C-TIER]
Santoryu: Ul-Tora Gari | Ittoryu: Baki | Nitoryu: 720 Pound Ho | Nitoryu Nigiri: Toro Samon | Ittoryu: 360 Pound Ho | Santoryu: Gyuki Yuzume | Santoryu: Hyokindama | Ittoryu: Yakkodori
[D-TIER]
Santoryu: Toro Nagashi | Santoryu: Yasha Garasu | Santoryu: Karasuma Gari | Santoryu: Daibutsu Giri | Santoryu: Gazami Dori | Santoryu: Ushi Bari | Nitoryu: Sai Kuru | Nitoryu: Taka Nami
[UTILITY]
Kitsunebi-ryu: Homura Saki | Nitoryu: Clear Lance
I factored in attack potency, destructive capacity, and the skill of the techniques, in that weighted order. If a pre-timeskip move had a post-timeskip upgraded variant, I excluded it from the list. Zoro doesn't typically use his pre-TS versions, with Sanzen Sekai being a notable exception (which is why I kept it, since he uses it against Pica).
Since KOH can work as an amp for existing techs, I ended up not including Hiryu Jigoku.