another option is octopus agile, it's not specifically an EV tariff and anyone can access it but it's beneficial if you have an EV
the main tariff people use on here is Tracker
This gives you a daily unit rate for electricity (and gas) which has strictly been below the price cap significantly
Last 30 days the average unit rate for elec was 16.91p and gas 3.96p in the north east region
It's good for average cheap electricity and gas, well below the cap and with no load shifting needed (this is moving your usage of high elec usage to cheap times)
The other suggestion is agile
Energy for the day is priced into half hourly slots - essentially it's cheapest midnight to about 7am, fairly cheap during the day, expensive 4-7pm then cheaper again
The 4-7pm sounds dangerous as unit rates can be quite high then but it's so cheap the rest of the time ther it balances out.
Quite common for unit rates like 2-3p in the cheap times and there are even negative unit rate slots - they pay you a few p per unit. Octopus has an api so with a compatible charger it will automatically pick the cheapest unit rates to get you to your target charge percentage
When I compare tracker, which is already cheaper to most, to agile, agile comes up a couple of pounds less, with no shifting.
If you add an ev into that mix, so cheap charging is available overnight and you could do a few things like shift dishwasher or washing machine loads to then, then you'll save even more.
With all of these tariffs though you need some understanding of your usage curve and likelihood of ability to load shift.
If you can't avoid putting all your appliances on in peak time, the more expensive energy will offset the cheaper ev energy e.g agile 4-7 or eon next 7am-midnight (unit rate is 8p k. Eon next 7-midnight but then outside of that it's 30.6p, so it's great for charging your EV but if you don't have battery or solar or both, all your usage from 7am to midnight is at a cost significantly higher than the price cap so you'd always want to be load shifting if possible)
Other thing to consider is where your gas is at as you'd probably want to go dual
Supplier at the very least, which isn't faff for apps etc
No agile equivalent of gas so just tracker, unit rate on tracked averaged below 4p, with current price cap it's 6p, eon next quoted me 6.3p
This doesn't sound significant difference bur remember you use thousands of units - our last 12 months we've used 9300 kWh so at price cap that's £558 with price cap, £585 with eon and £362 with octopus. We are low users - average household uses 11,500kWh on gas so an even bigger difference in price -£690 price cap, £724 eon, £448 octopus.
No exit fees with agile or next but next is fixed for 1 year, after which you renew at the new price
This is significant because price caps are forecast to fall and you'd think the eon next unit rate for off peak is going to be tied in some way to that - they put the price up in jan when the price went up on the cap slightly - the q3 forecasts are saying 5p gas and 20p elec rates, again doesn't sound a lot but remember 11,500kWh units on gas and 2700kwh units in elec for average household.
So a lot of info there but key points in summary:
1) consider when you'll use your electricity, both in and out of cheap windows for any tariff, and ability / desire to load shift
2) consider what is forecast to happen with energy prices and how your chosen tariff will react to that
3) make sure charger is compatible with specific tariffs / api
4) don't forget to consider gas as it's a considesble part of your bill