Relatively recently we began to receive rewards in soulbound cards, which are not transferable and can only be won in daily and end of season chests, we are only in the 2nd season with them and I consider very useful some that I have obtained.
Although I have not yet obtained all 43 cards that exist and with 20 of them I can give you a good opinion about them, here I will talk about the 3 that I use the most and I like the most at the moment.

3 - Helios Matriarch

We start with an obvious option, the dragon summoner, which not only allows us to summon that element by selecting another one as a companion, but also gives us the option to "recruit" and even more, it increases our speed by 1.
That leaves it with many options of use, but I personally usually use it more to increase the speed of cards that already have enough and thus make it possible to dodge many hits, as I show you in this battle where even though he uses a summoner that decreases the speed, it is like he would be contradicting that action and leaves the battle even when it should not:

LINK DE LA BATALLA / LINK TO THE BATTLE

2 - Riverboat Captain

In second place we have the water element card that just at level 1 already gives 2 magic attack power but also having the explosion ability that will help to get rid of those support cards that can be quite annoying if you don't eliminate them as soon as possible, but also having 4 life for only 6 mana seems perfect to withstand enough hits before even falling to 1st position.
In this example I show you a battle where the "Aimless" rule would leave to luck where the attacks would go, this makes it possible to take advantage of even more "explosion" since having 2 monsters in the adjacencies of your attack would be 3 that receive damage.

LINK DE LA BATALLA / LINK TO THE BATTLE

1 - Venari Marksrat

Number 1 could not be other than a card that has my favorite ability, "Martyr" but not only that, it is also a neutral card which I can combine it with countless cards of all possible elements, this would leave it as an indispensable card to be used in battles because with a cost as low as 3 it can give you a lot of advantage if you know how to use it as it should.
In this clear example I show you how I use it to balance the battle clearly towards me, taking advantage that the rules dictated that we could only use cards with ranged attack, but also that all of them will have the ability "opportunistic" was strategically placed there to increase the stats of my 2 cards that have the ability "point blank".

LINK DE LA BATALLA / LINK TO THE BATTLE

Final Comments:
I know that these are not even close to the best of this type of cards, but we are just starting and I who stay in silver fighting still can not even unlock an epic or legendary card to try more variety but I know that then we can continue testing.
The way to get the cards makes that not everyone can have all of them from the beginning as before that you only went to the market and bought them if you liked, but this gives more dynamics and playability the fact that only active players can have them.
Needless to say that I like the fact of raising not only my own deck of cards but also my own power and be able to continue rising little by little, do not miss this opportunity and continue to get these rewards.

Great greetings to all Splinterland players.
Here is my referral link for those who have not yet started to play and are interested in the game: https://splinterlands.com?ref=titopx
All the Captures were made from the splinterlands.com website and edited in Photoshop.