Feb. - LGBT History Month (UK) (Started 2005)
LGBT History Month is a month-long annual observance of lesbian, gay, bisexual, and transgender history and the history of gay rights and related civil rights movements. In the United Kingdom, it is observed during February to coincide with a major celebration of the 2005 abolition of Section 28.
https://lgbtplushistorymonth.co.uk/resources/for-parents/
March 31 - International Transgender Visibility Day
The event was created by transgender activist, Rachel Crandall Crocker of Michigan in 2009 as a reation to the lack of LGBTQ+ recognition of transgender people.
May 17 - International Day Against Homophobia
May 17, or the International Day Against Homophobia and Transphobia (IDAHO or IDAHOT or IDAHOBiT), as it is widely recognized, is an essential feature in the international LGBT rights calendar. In the 9th edition, in 2013, commemorations took place in almost 120 countries in all world regions. The day aims to coordinate international events that raise awareness of LGBT rights violations and stimulate interest in LGBT rights work worldwide. IDAHO's date was chosen to commemorate the decision to remove homosexuality from the International Classification of Diseases of the World Health Organization (WHO) in 1990. The International Day Against Homophobia (or "IDAHO") established the IDAHO Committee to coordinate grassroots actions in different countries, promote the day, and lobby for the official recognition of May 17.
https://www.familylives.org.uk/advice/bullying/general-advice/what-is-homophobic-bullying
June - Pride Month
June is celebrated as Pride in honor of the Stonewall Riots, though Pride events occur all year round. Gay pride, or LGBT pride, is the positive stance against discrimination and violence toward lesbian, gay, bisexual, and transgender (LGBT) people to promote their self-affirmation, dignity, equality rights, increase their visibility as a social group, build community, and celebrate sexual diversity and gender variance.