Shrimati Radharani is also mentioned in Srimad Bhagavatam but without taking her name because Sukadev Goswami was Srimati Radharani's parrot & if he would have uttered Radharani's name then he would have entered into trance & could not have finished katha for Parikshit. Thread.. https://twitter.com/TIinExile/status/1295364734250713089

While Srila Vyasadeva was writing Srimad Bhagavatam and explaining Krsna’s romantic dance with the Gopis He was meditating on Srimati Radharani, but due to fear of falling into trance he did not directly mention Her name in the Srimad Bhagavatam.

The name Radha is very sensitive, if by chance Srila Vyasadeva or Sri Sukadeva Goswami would have repeated it, the Srimad Bhagavatam would have not been completed. Sukadeva Gosvami is referred in Bhagavatam as Suk uvacha. Suk in Sanskrit means Parrot. He was Radharani's Parrot.

Furthermore King Pariksit, the listener of Srimad Bhagavatam, only had seven days to live and was anxious to hear it in its totality, therefore Sri Sukadeva Goswami was afraid to mention Radharani’s name because if he did he would have gone into a trance.

That is why Her name is not directly mentioned either by Srila Vyasadeva in writing, nor by Sri Sukadeva Goswami while speaking the Srimad Bhagavatam. In this way, Radha’s name is kept concealed in the Srimad Bhagavatam. 

Radharani is referred indirectly in the following verse:

SB10.30.28:
anayaradhito nunam
bhagavan harir isvarah
yan no vihaya govindah
prito yam anayad rahah

'Dear friends, the gopi who has been taken away by Krsna to a secluded place must have worshiped the Lord more than anyone else.'

"The name Radha is derived from this verse (SB 10.30.28), from the words anayaradhitah, meaning "by Her the Lord is worshiped." Sometimes the critics of Srimad-Bhagavatam find it difficult to find Radharani's holy name in that book,.....

...but the secret is disclosed here in the word aradhita, from which the name Radha has come. Of course, the name of Radharani is directly mentioned in other Puranas. This gopi's worship of Krsna is topmost, and therefore Her name is Radha, or 'the topmost worshiper.'"

In SB 10.32.4 Sukadeva has said, "kacit karambujam saurer jagrhe 'njalina - one of them seized Krsna's hand in her folded palms." Kacit refers to "*one* of them". That one is Radharani.

SB10.30.38
evam uktah priyam aha
skandha aruhyatam iti
tatas cantardadhe krsnah
sa vadhur anvatapyata
"After being addressed by a particular gopi, Krsna told Her, Climb up on My shoulder. Saying this He suddenly disappeared. His beloved consort then immediately felt great remorse

SB 10.30.26 describes how after Krsna left the rasa dance with one special gopi the other gopis went searching for "vadhvah"- that special gopi (Radharani).

SB10.47.11
kacin madhukaram drstva
dhyayanti krsna-sangamam
priya-prasthapitam dutam
kalpayitvedam abravit
"*One* of the gopis, while meditating on Her previous association with Krsna, saw a honeybee & imagined it to be a messenger sent by Her beloved. Thus She spoke as follows

The word "kacin" in this verse, meaning "one of the gopis" refers to Radha.

Aside from the Bhagavatam, Radharani is described elaborately in Brahma-vaivarta, Padma, and Narada Puranas as well as Garga Samhita.

4th chapter of Ujjvala-nilamani, "Sri Radha-prakaranam" texts 3 &4, Rupapada cites the Gopala-tapani Upanisad (of Atharva Veda), Uttara-khanda, where Radha is called Gandharvi & the Rg Veda-parisista where Her name Radha is mentioned. There She is described as consort of Madhava

'From the Vedic literature we come to know that Sri Radharani is referred to as 'Gandharvi' in the second part of the Gopal Tapani, and as 'Radha' in the Rg Parishistha.'

From Padma Purana to many other Puranas and other Vedic scriptures directly mentions Shrimati Radharani name.

Lord Siva states in the Sammohana Tantra thus, tasmaj jyotir abhud dvedha radha-madhava rupakam, “The Supreme Lord Sri Krsna, although one and alone, He becomes two—Radha and Madhava (another name of Lord Krsna) just to perform His loving pastimes.”