Karalajanaka

Karalajanaka was advised by Vasishta as per Mahabharata Shantiparva Chapter s 302- 308.

https://www.google.com/search?q=Karalajanaka

Parashara

On another occasion Janaka had a discussion with the sage Parashara on prosperity as per Mahabharata Shantiparva Chapter 296.

https://www.google.com/search?q=Parashara+Janaka

Mandavya

Once the sage Mandavya asked Janaka many questions on mirages that he answered as per Mahabharata Shantiparva Chapter 296.

https://www.google.com/search?q=Mandavya+Janaka

Kshemadarshi

Once the king Kshemadarshi fought Janaka. When Janaka was about to lose, the sage Kalakavrikshiya advised him to give his daughter to Kshemadarshi and make peace. Janala dod so as per Mahabharata Shantiparva Chapter 106 verse 21.

https://www.google.com/search?q=Kshemadarshi

Pratarddana

Once a king named Pratarddana fought Janaka. Janaka’s army stood flummoxed but he showed them sights of heaven and hell and motivated them as per Shantiparva Chapter 99 verse 4.

https://www.google.com/search?q=Pratarddana

Ashma

https://www.google.com/search?q=Ashma+janaka

Marutta

After Ravana captured Sita and she was living in the Ashoka grove, he sent a rakshasa named Marutta in the form of Janaka to influence her. But Sita did not relent as per Kambaramayana Sundarakanda.

https://www.google.com/search?q=Kamba+Ramayanam+Sundarakanda

dhwaja

Seeradhwaja was childless when once he found a baby in a furrow. He wanted to raise her as his own and at that instant, a divine voice asked him to do exactly that. This was Sita as per Ramayana Ayodhyakanda Sarga 118.

https://www.google.com/search?q=Seeradhwaja

Kushadhwaja had 3 daughters-

1. Urmila(married to Lakshmana), 
2. Mandavi (married to Bharata) and 
3. Shrutakeerthi (married to Shatrughna) 

as per Ramayana Balakanda Sarga 71.

Note Sita one son is named Kusha

https://www.google.com/search?q=Kushadhwaja

yama

https://www.google.com/search?q=yama+janaka