Twenty8 is exclusive with their minimum investment amount, looking at their current stats the average invested amount is around £20k per/investor. They picked 28 investments based on research by NESTA and Intelligent Partnership which claim early-stage portfolios need at least 28 investment to have a 95% chance of securing at least one 10x investment. Having said that their current portfolio is interesting and it might work out. Interestingly they also have a Growth Fund including over 100 companies but that was done over many years.
Seedrs time frame for the 100 companies is very ambitious. They want 100 companies in 12 months or less. Seedrs Autumn Portfolio 2018 Update shows 168 SEIS & EIS completed deals in 2017, so it is possible you will end up investing in every EIS pitch on Seedrs. Worth checking out their latest update report, it even show stats including & excluding Revolut. I would like to see a serious early stage (S)EIS fund which is selective and does more due diligence but I do not see this happening anytime soon. Of course investing in all of the pitches on Seedrs could work.
Finally Seedcamp raised a private invite only fund on Seedrs earlier on in the year. It would be good to see Seedrs land funds like Seedcamp, like they have done with Ignite100, and Collider accelerators.