clearpoll is working on the problem which is very much required in today's senerio because it is working on the problem of fair polling and the power of decision making of the people. In today's world people are being highly manipulated through unfair poll shown in tv channel and other platform. In clearpoll people can vote through clearpoll app onces you have voted you cannot change because it is stored in a blockchain and it cannot be manipulated like it is done in news channel. This is very much essential and i think it will be very impactful if the team work properly. And the supply of the coin is also very less it is only 7 million so if the project does well then you can see a great boom in a price. 
electra coin is the coin which is very much suggest with the name that it is working on the speed. They want that their transaction should be at the speed of electricity. It is an open source project that's why they are always developing and make changes on the coding so that the transaction speed increases and they achieve the goals which they have set for themselves. And also the transaction fees is almost zero so it solved the big problem that bitcoin and ethereum has. You can grab it now because it is very cheap and hold it for a year or two and see where this project goes in future.
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Holochain you can also called holochain as a third generation cryptocurrency after bitcoin and ethereum. It is a very new concept that's why it has still not got an acceptance on a large scale. It is very ecofriendly as compared to bitcoin and ethereum which uses lots of electricity and that's why it has to face criticism. But in holochain that's not a problem because it uses your computer power to run which is very less. It also solves the problem of privacy because you are the owner of your data and you don't have to give your information to any government or third party. You can but this currency and hold it for a long term because it is very cheap and the project and team is also very good. This is my short review about all this three coin. Do your own research before investing in any coin. I just wanted to put some light on these cryptocurrency.