-- Attack of the Saiyans --
Son Goku: 334
-- No weights: 416
- Post-training: 8,000
-- Kaioken x2: 16,000
-- Kaioken x3: 24,000
-- Kaioken x4: 32,000
Piccolo: 322
-- No weights: 408
- Post-training: 3,500
Son Gohan: 1
-- Angry: 1,307
- Post-training: 981
Kuririn: 206
-- Post-training: 1,770
Tenshinhan: 250
-- Post-training: 1,830
Chaozu: 132
-- Post-training: 720
Yamcha: 177
-- Post-training: 1,480
Yajirobe: 100
-- Post-training: 660
Kame-sennin: 139
Raditz: 1,350
Saibamen: 1,200
Nappa: 6,000
Vegeta: 18,000
-- Oozaru (injured): 70,000
Mr. Popo: 255
God: 275
Enma Daioh: 2,300
North Kaio: 3,500
A couple of notes: Nappa's highest official battle power is 4,500, but Goku said he'd have some trouble against him. Also worth noting that Tenshinhan's Shin Kikoho and Chaozu's self destruction both presented threats to his life. I subscribe to the idea that Raditz was slightly stronger than the Saibamen, but 1,500 is bit too exaggerated.
-- Namek --
Kuririn: 1,770
-- after unlocking potential: 13,000 and rising
-- vs Ginyu: 27,000 and rising
-- vs Freeza: 150,000 and rising
Son Gohan: 1,500
-- after unlocking potential: 14,000 and rising
-- vs Ginyu: 29,000 and rising
-- vs Freeza: 200,000 and rising
Vegeta: 24,000
-- after healing: 30,000
-- after Senzu: 75,000 and rising
-- vs Freeza: 400,000
- post-Zenkai: 2,400,000
Piccolo: 125,000
-- post-fusion, weighted clothing: 1,250,000
-- post-fusion, no weights: 1,562,500
Son Goku: 90,000
-- Kaioken x2: 180,000
- Post-zenkai: 3,000,000
-- Kaioken x20: 60,000,000
-- Super Saiyan: 150,000,000
Nail: 42,000
Kiwi: 18,000
Dodoria: 20,000
Zarbon: 22,500
-- Transformed: 31,000
Guldo: 12,000
Recoome: 40,000
Jeice: 40,000
Burter: 40,000
Ginyu: 120,000
-- In Goku's body: 23,000
Freeza: 530,000
-- Second form: 1,400,000
-- Third form: 1,950,000
-- True Form: 3,600,000
----- 50%: 60,000,000
----- 70%: 84,000,000
----- 100%: 120,000,000
Mecha Freeza: 94,500,000
-- Unseen Full Power: 135,000,00
King Cold: 92,000,000
Future Trunks: 3,000,000
-- Super Saiyan: 150,000,000
Son Goku: 3,200,000
-- Super Saiyan: 160,000,000
Mostly all self-explanatory. The biggest power boosts in the series occur here thanks to Freeza's multiple forms. Toriyama oversights lead us to headcanon that Gohan and Kuririn's battle power had been rising all throughout the arc, as well as Vegeta's at a certain point. Both Trunks and Goku were holding back in their sparring match, so it's not a fair gauge of either of the two's strength.
-- Artificial Humans --
Son Goku, sick: 3,300,000
-- Super Saiyan, sick: 165,000,000 and decreasing
-- post-Kamehameha: 110,000,000 and decreasing
Vegeta: 3,800,000
-- Super Saiyan: 190,000,000
Piccolo: 12,000,000
-- Full Power: 120,000,000
----- No weights: 150,000,000
Artificial Human #19: 70,000,000
-- post-Kamehameha: 135,000,000
-- after absorbing Ki from Goku and Vegeta: 145,000,000
Artificial Human #20: 72,000,000
-- after absorbing Vegeta and Piccolo's Ki: 100,000,000
Future Trunks: 3,700,000
-- Super Saiyan: 185,000,000
Kuririn: 1,700,000
Yamcha: 1,000,000
Tenshinhan: 1,400,000
Gohan: 2,300,000
There is no guarantee that the #19 and Dr. Gero surpassed Freeza before Ki adsorptions, but I'd also argue it doesn't matter since they're defeated by a healthy Super Saiyan just as Freeza was. Kuririn and Gohan's strength have acclimated and they, along with the humans, have trained several years for this; the Artificial Humans mistake Yamcha for Goku, and although the last data they may have had was on Saiyan arc Goku, I still think this warrants a big power increase. Piccolo's power boost is the most egregious.
Piccolo, post-fusion: 210,000,000
-- No weights: 262,500,000
Artificial Human #18: 255,000,000
Artificial Human #17: 262,500,000
Artificial Human #16: 290,000,000
Imperfect Cell: 200,000,000
-- After absorbing humans: 290,000,000
Semi-Perfect Cell: 350,000,000
Tenshinhan: 1,400,000
-- Shin Kikoho: 140,000,000
Vegeta, post RoSaT: 6,000,000
-- Super Saiyan: 300,000,000
-- Grade 2: 420,000,000
Future Trunks, post-RoSaT: 6,000,000
-- Super Saiyan: 300,000,000
-- Grade 2: 420,000,000
-- Grade 3: 600,000,000
Perfect Cell: 650,000,000
-- Cell Games --
Mr. Satan: 7
Piccolo: 775,000,000
Future Trunks: 13,000,000
-- Super Saiyan: 650,000,000
-- Grade 2: 910,000,000
Vegeta: 13,000,000
-- Super Saiyan: 650,000,000
-- Grade 2: 910,000,000
Cell Jr: 950,000,000
Son Goku, post-RoSaT: 15,000,000
-- Mastered Super Saiyan, 50%: 750,000,000
-- Mastered Super Saiyan: 1,500,000,000
Gohan: 20,000,000
-- Mastered Super Saiyan: 2,000,000,000
-- Super Saiyan 2: 4,000,000,000
Perfect Cell: 2,000,000,000
--Super Perfect Cell: 4,000,000,000
Another big power gap emerges. Goku's 50% power at Karin lookout stuns Vegeta and Trunks, implying he's superior to them at their best. This is where I apply my theory that MSS is Grade III condensed. This avoids bloating the Saiyan's base powers to ridiculous lengths when their training was focused on mastery of the Super Saiyan form. Of course, then, the Saiyans and Piccolo must all surpass this level of power showcased by Goku in time for the Cell Games. Even this power is nothing to Gohan, however, who seems to take everything Cell throws at him and shrug it off. Cell gains a Super Saiyan 2 of his own and gets back on equal footing with Gohan, who needs to catch Cell off-guard to win.
Many questions one may raise here: why assume Goku's 50% power surpassed Vegeta and Trunks? They could just be stunned he had that much power in his normal Super Saiyan form without any upgrades. Certainly possible, but they didn't know Goku had achieved Grade 2 and 3 already. For all they know, Super Saiyan was his strongest form. So if they were shocked by his strength, then it's because he was stronger than them. Another question: Gohan said he was at half strength during the Kamehameha struggle, doesn't this mean Super Saiyan 2 boost is larger than 2x? Another valid question. I just interpret it as lack of confidence. Goku himself says he has the power to win. If you really want to scrutinize things, you can say that Gohan powered-up due to anger at the last moment.
-- Future Timeline --
Future Gohan: 2,000,000
-- Super Saiyan: 100,000,000
Artificial Human #18: 175,000,000
Artificial Human #17: 170,000,000
Future Trunks, after returning: 13,000,000
-- Super Saiyan: 650,000,000
-- 3 years later: 15,000,000
----- Super Saiyan: 1,500,000,000
Imperfect Cell: 300,000,000
By the time Trunks fights Cell, three years have passed since he killed the artificial humans, plenty of sufficient time to master the Super Saiyan form.
-- Majin Boo arc --
]Mr. Satan: 6.9
Videl: 7.5
Spopovich: 8
Son Gohan: 17,000,000
-- Super Saiyan: 1,700,000,000
-- Super Saiyan 2: 3,400,000,000
Son Goten: 10,000,000
-- Super Saiyan: 1,000,000,000
Trunks: 11,000,000
-- Mastered Super Saiyan: 1,100,000,000
Piccolo: 1,300,000,000
Kaioshin: 1,600,000,000
Kibito: 25,000,000
Kibitoshin: 5,500,000,000
The kids shouldn't be underestimated because of their age. They packed enough of a punch to nearly kill #18, they shocked Piccolo, and Gohan even admitted they were almost as strong as he was. A couple of notes: Super Boo gains Piccolo's appearance and in GT Trunks claims Piccolo is stronger than him; in Super, the kids fight off multiple Cell Jrs in #17's island. A level between the Cell Jrs and Piccolo seems accurate to me.
Pui Pui: 7,500,000
Yakon: 30,000,000
Dabra: 4,200,000,000
Son Goku: 25,000,000
-- Super Saiyan: 2,500,000,000
-- Super Saiyan 2: 5,000,000,000
-- Super Saiyan 3: 20,000,000,000
Vegeta: 22,000,000
- Majin Vegeta: 25,000,000
-- Super Saiyan: 2,500,000,000
-- Super Saiyan 2: 5,000,000,000
Goku and Vegeta both surpassed Gohan from the Cell Games, but not by an absurd margin. Dabra is superior to Super Perfect Cell, regardless of whether Gohan is using his SS or SS2 form.
Majin Boo: 15,000,000,000
-- Evil Boo: 8,500,000,000
-- Mr. Boo: 6,500,000,000
Son Goten, post-training: 11,000,000
-- Super Saiyan: 1,100,000,000
Trunks, post-training: 12,000,000
-- Super Saiyan: 1,200,000,000
Gotenks: 40,000,000
-- Super Saiyan: 4,000,000,000
- Post training: 50,000,000
-- Super Saiyan: 5,000,000,000
-- Super Saiyan 3: 40,000,000,000
Gohan, post-training: 26,000,000
-- Super Saiyan: 2,600,000,000
-- Super Saiyan 2: 5,200,000,000
-- Ultimate: 50,000,000,000
Super Boo: 35,000,000,000
-- after absorbing Gotenks: ~75,000,000,000
-- after absorbing Gohan: ~85,000,000,000
Vegetto: 1,500,000,000
-- Super Vegetto: 150,000,000,000
Kid Boo: 20,000,000,000
I once considered SS Gotenks stronger than SS3 Goku. At a certain point, even base Gotenks stronger than SS3 Goku. But since there's nothing concrete in the manga to support anything besides SS3 Gotenks being stronger than SS3 Goku, I've dialed down the fusion's power a bit. Goku considered it a gamble, not a certainty.