If you have a small car or a 2.5L diesel engine, this is sufficient, and from a reputable brand. Click the link and choose 8000mAh. Based on my google-fu, some sites say a Peak current of 800A can start a 4L diesel engine or 6L petrol.
Baseus Car Booster 800A Power Bank Battery Jump Starter 12V Auto Starting Device Charger Car Starter 8000mAh Emergency Battery
—Capacity: 8000mAh/3.7V/29.6Wh
—Rated output capacity: 4900mAh
—Input: 5V/2.1A(Max)
—USB output: 5V2.4A(Max)
—Start-up voltage: 12V
—Start-up current: 400A
—Peak current: 800A
—Suitable models : gasoline vehicles with a displacement of less than 4.0 L or diesel vehicles with a displacement of Less than 2.5 L
Suitable for 90% vehicles
12V petrol vehicles with displacement not exceeding 4.0L
12V diesel vehicles with displacement not exceeding 2.5L
Vehicle type:Car/SUV/Business car/Electric car/Motorcycle/Van/Pick up/Small truck
I can vouch for the limit. I started a 4l diesel with one off these, it was quite warm after.