04 April 2019 :

(upated Junly 18, 2021) At least 167 executions in 2021 so far in Iran. They were at least 284 in 2020, 298 in 2019, and 328 in 2018, according to Hands off Cain data as you can see at this link

This spreadsheet puts together data collected from different sites, favoring (for a criterion of uniformity) the sites managed by Iranians publishing in English. However, transliteration from Persian (Farsi) to Latin characters may be ambiguous, and often options are given for person or place names. In Iran the dates follow the Persian calendar, so sometimes even dates present some uncertainty.
The high number of executions of unidentified people (abbreviated as unk) may have caused some inaccuracy, because sometimes it is not enough to "deduce" from prisons, dates and crimes wether it is the same case being reported by different websites. After making all reasonable checks, the possibility remains that some "unidentified" may have been listed twice, or not listed at all.
However, to facilitate further verification, for each alleged execution the internet source is indicated, a source which in turn often leads back to the Persian source.

The main reference sites for this database are:

https://iranhr.net/en 
Iran Human Rights

https://iranhrdc.org 
Iran Human Rights Documentation Center

https://iran-hrm.com 
Iran HRM (Human Rights Monitor)

https://hengaw.net/en 
Hengaw Organization for Human Rights (focused on the Kurdish minority)

http://balochwarna.com 
Balochwarna News (focused on the Baloch minority)

http://kurdistanhumanrights.net/en 
KHRN (Kurdistan Human Rights Network (focused on the Kurdish minority)

http://www.capitalpunishmentuk.org 
British site tracking executions worldwide

https://ipa.united4iran.org/en 
Iran Prison Atlas

https://iranhumanrights.org IHRDC 
Iran Human Rights Documentation Center

https://mafnews.de/english 
Center of Democracy and Human Rights in Kurdistan (focused on the Kurdish minority)

https://women.ncr-iran.org 
NCRI (National Council Of Resistance Of Iran Women Committee)

https://www.en-hrana.org 
Human Rights Activists News Agency

https://www.iranrights.org 
Human Rights & Democracy for Iran

https://www.ncr-iran.org/en 
NCRI (National Council Of Resistance Of Iran Foreign Affairs Committee

https://en.javanehha.com/ 
Javanehha “No to prison, no to execution”

The main journalistic sources considered "official" (or otherwise pro-government) are: Fararu, Fars News Agency, ILNA (Iranian Labour News Agency), IRIB (Islamic Republic of Iranian Broadcasting), IRNA (Islamic Republic News Agency), ISNA (Iranian Students' News Agency), Javan, Mizan, Rokna, Tasnim News Agency, YJC (Young Journalists Club).

Most information on executions in Iran actually comes from other sources related to human rights or political opposition.