In melee only battles, you can use melee units with a dual attack. These dual attack cards can be very useful as your opponent is not expecting a second type of attack and most likely hasn't catered for it.
Take this recent Melee Only battle I had. Quora's one of my favorite dual attackers. Not only does she have decent health, speed as well as dual attack, she is also a self-healer.
So, against my opponent who had two strong attackers as well as additional Thorns damage, could 1 Quora survive?
Not looking good at the end of the first round. I was down to four health and with my opponent doing 6 damage per round, I thought I was surely done for.
But thanks to a miss by my opponent, I was able to turn the tables around. And by round 3, I got his Cursed Winduku down to 2 health. If it weren't for my opponent's summoner, giving a -1 magic debuff, it would have been an even easier victory. You can catch a replay of the entire battle here: https://splinterlands.com/battle/sl_7838e3d2ea1599b3351f3860cfbe12d0?ref=charcoalbuffet
Magic and Melee Dual Attackers
Excluding Gladiator cards, there are 5 magic and melee dual attackers that you can pick up on the market. If you're playing in the modern leagues, only the first three are eligible at the moment. All of them are strong cards that would do well in your lineup.