Among them is Khaled Nordin, an Umno vice-president and a former Johor menteri besar.
Khalid is the Barisan Nasional candidate in a three-cornered fight for the Kota Tinggi parliamentary seat.
In 2018, Khaled had unexpectedly been defeated by Pakatan Harapan (PH) candidate Hassan Karim in Pasir Gudang, who won with a majority of 24,726 votes. Khaled was also defeated in the Permas state seat.
Umno Supreme Council member Johari Ghani is also returning to the battleground in the Titiwangsa parliamentary constituency where he lost to PH candidate Rina Harun by a 4,139-vote margin in 2018.
In the current election, he is in a four-cornered fight with Khairuddin Abu Hassan (GTA-Pejuang), Khalid Samad (PH-Amanah) and Rosni Adam (PN-PAS).
Also in the spotlight is PKR deputy president Rafizi Ramli who did not contest in Pandan in 2018 over doubts about his eligibility to stand for election as he had filed an appeal against a 30-month jail sentence for leaking banking details belonging to the National Feedlot Corporation and its chairman.
Rafizi was Pandan MP from 2013 to 2018.
Another candidate making an appearance in the Pandan constituency is former MCA president Ong Tee Keat who is now with Warisan.
He had served as the Pandan MP for two terms from 2004 to 2013, and was defeated by Rafizi in 2018. Ong, a former transport minister, then took a four-year break from politics.
In the Batu parliamentary seat, former PKR vice-president Tian Chua made a surprise move by contesting as an independent candidate against P Prabakaran (PH-PKR), who had been elected in 2018 when Tian Chua was disqualified.
The other contenders are Wan Azliana Wan Adnan (GTA-Pejuang), Azhar Yahya (PN-PAS), Naganathan Pillai (Warisan) and A Kohilan Pillay (BN-MIC), and four other independent candidates: Siti Kasim, Zulkifli Fattah, Too Gao Lan and Nur Fathiah Syazwana @ Cleo
Tian Chua first contested in the Batu constituency in 2004 but lost to Gerakan candidate Ng Lip Yong but returned in 2008 to win the seat and defended it in 2013.
He said he wished to return to the seat to keep his promise to voters.
He was disqualified from contesting in 2018 following a High Court decision in March 2018 upholding his conviction and RM2,000 fine for insulting the honour of a policeman.
Another former MP trying for a comeback is former four-term Jempol MP Mohd Khalid Yunus, 79.
His return to the electoral fray on a GTA-Pejuang ticket comes 18 years after Barisan Nasional dropped the four-term Jempol MP in 2004. He is among four candidates vying for the seat.