Associations: constitution, board of directors, and sanctions.

Yes. The Autonomous Communities have their own implementing regulations, including the following:

ANDALUSIA

• Organic Law 2/2007, of March 19, on the reform of the Statute of Autonomy for Andalusia (BOE no. 68, of March 20).
• Royal Decree 304/1985, of February 6, on the transfer of functions and services (BOE no. 62, of March 13).
• Law 4/2006, of June 23, on Associations of Andalusia (BOJA no. 126, of July 3; BOE no. 185, of August 4).
• Decreto 152/2002, of March 21, approving the Regulations on the Organization and Operation of the Registry of Associations of Andalusia (BOJA number 69, of June 13).

ARAGON

• Organic Law 5/2007, of April 20, on the reform of the Statute of Autonomy of Aragon —Article 71— (BOE no. 97, of April 23).
• Royal Decree 1054/1994, of May 20, on the transfer of functions and services (BOE no. 148, of June 22).

CANARY ISLANDS

• Organic Law 1/2018, of November 5, on the reform of the Statute of Autonomy of the Canary Islands —Article 110— (BOE no. 268, of November 6).
• Royal Decree 1205/1985, of July 3, on the transfer of functions and services (BOE no. 175, of July 23).
• Law 4/2003, of February 28, on Associations of the Canary Islands (BOE no. 78, of April 1).
• Decree 12/2007, of February 5, approving the Regulations for Associations of the Canary Islands (Official Gazette of the Canary Islands no. 38, of February 21).

CANTABRIA

• Statute of Autonomy. Organic Law 8/1981, of December 30  (BOE no. 9, of January 11, 1982), amended by Organic Law 2/1994, of March 24 (BOE no. 72, of March 25), and by Organic Law 11/1998, of December 30 (BOE no. 313, of December 31).
• Royal Decree 1388/1996, of June 7, on the transfer of functions and services (BOE no. 156, of June 28).

CASTILLA – LA MANCHA

• Statute of Autonomy. Organic Law 9/1982, of August 10  (BOE no. 195, of August 16), amended by Organic Law 7/1994, of March 24 (BOE no. 72, of March 25) and by Organic Law 3/1997, of July 3 (BOE no. 159, of July 4).
• Royal Decree 376/1995, of March 10, on the transfer of functions and services (BOE no. 93, of April 19; correction of errors in BOE no. 114, of May 13).

CASTILLA Y LEÓN

• Organic Law 14/2007, of November 30, on the reform of the Statute of Autonomy of Castilla y León —Article 71— (BOE no. 288, of December 1).
• Royal Decree 1687/1994, of July 22, on the transfer of functions and services (BOE no. 216, of September 9).

CATALONIA

• Organic Law 6/2006, of July 19, on the reform of the Statute of Autonomy of Catalonia —Article 118— (BOE no. 172, of July 20).
• Law 4/2008, of April 24, of the third book of the Civil Code of Catalonia, relating to legal entities (BOE no. 131 of May 30).
• Royal Decree 3526/1981, of December 29, on the transfer of services (BOE no. 47, of February 24, 1982).
• Royal Decree 1266/2007, of September 24, on the transfer of functions from the State Administration to the Generalitat of Catalonia regarding the declaration of public utility of associations and the application of tax benefits to associations and foundations (BOE no. 230, of September 25).

COMMUNITY OF MADRID

• Statute of Autonomy. Organic Law 3/1983, of February 25  (BOE no. 51, of March 1), amended by Organic Law 10/1994, of March 24 (BOE no. 72, of March 25) and by Organic Law 5/1998, of July 7 (BOE no. 162, of July 8).
• Royal Decree 2372/1994, of December 9, on the transfer of functions and services (BOE no. 310, of December 28).

CHARTERED COMMUNITY OF NAVARRE

• Organic Law 13/1982, of August 10, on the reintegration and improvement of the Chartered Regime of Navarre —Article 44.19— (BOE no. 195, of August 16), amended by Organic Law 1/2001, of March 26 (BOE no. 75, of March 28) and by Organic Law 7/2010, of October 27 (BOE no. 261, of October 28).
• Royal Decree 225/1986, of January 24, on the transfer of services (BOE no. 36, of February 11).

VALENCIAN COMMUNITY

• Statute of Autonomy (Article 31.23). Organic Law 5/1982, of July 1  (BOE no. 164, of July 10), reformed by Organic Law 5/1994, of March 24 (BOE no. 72, of March 25) and by Organic Law 1/2006, of April 10 (BOE no. 86, of April 11).
• Royal Decree 1039/1985, of May 25, on the transfer of functions and services (BOE no. 157, of July 2).
• Law 14/2008, of November 18, on Associations of the Valencian Community (DOCV no. 5900, of November 25; BOE no. 294, of December 6).

EXTREMADURA

• Organic Law 1/2011, of January 28, on the reform of the Statute of Autonomy of the Autonomous Community of Extremadura (BOE no. 25, of January 29).
• Royal Decree 62/1995, of January 24, on the transfer of functions and services (BOE no. 40, of February 16).

GALICIA

• Organic Law 1/1981, of April 6, on the Statute of Autonomy for Galicia (BOE no. 101, of April 28).
• Organic Law 16/1995, of December 27, on the transfer of powers to the Galician Autonomous Community (BOE no. 310, of December 28).
• Royal Decree 1639/1996, of July 5, on the transfer of functions and services (BOE no. 184, of July 31).
• Royal Decree 1080/2008, of June 30, on the expansion of functions of the State Administration transferred to the Autonomous Community of Galicia, regarding associations: Declaration of public utility of associations and application of tax benefits (BOE no. 158, of July 1).

BALEARIC ISLANDS

• Organic Law 1/2007, of February 28, on the reform of the Statute of Autonomy of the Balearic Islands (BOE no. 52, of March 1).
• Royal Decree 120/1995, of January 27, on the transfer of functions and services (BOE no. 44, of February 21).

LA RIOJA

• Statute of Autonomy. Organic Law 3/1982, of June 9  (BOE no. 146, of June 19), amended by Organic Law 3/1994, of March 24 (BOE no. 72, of March 25) and by Organic Law 2/1999, of January 7 (BOE no. 7, of January 8).
• Royal Decree 2375/1994, of December 9, on the transfer of functions and services (BOE no. 310, of December 28).

BASQUE COUNTRY

• Statute of Autonomy (Article 10.13). Organic Law 3/1979, of December 18  (BOE no. 306, of December 22).
• Royal Decree 2590/1985, of December 18, on transfers (BOE no. 11, of January 13, 1986).
• Law 7/2007, of June 22, on Associations of Euskadi (BOPV no. 134 ZK, of July 12; BOE no. 250, of October 17, 2011).
• Decree 145/2008, of July 29, approving the Regulations of the General Registry of Associations of the Basque Country (BOPV no. 162 ZK, of August 27).
• Decree 146/2008, of July 29, approving the Regulations on Public Utility Associations and their Protectorate (BOPV no. 162 ZK, of August 27).

PRINCIPALITY OF ASTURIAS

• Statute of Autonomy. Organic Law 7/1981, of December 30  (BOE no. 9, of January 11, 1982), amended by Organic Law 3/1991, of March 24 (BOE no. 72, of March 25), by Organic Law 1/1994, of March 24 (BOE no. 72, of March 25) and by Organic Law 1/1999, of January 7 (BOE no. 7, of January 8).
• Royal Decree 846/1995, of May 30, on the transfer of functions and services (BOE no. 161, of July 7).

REGION OF MURCIA

• Statute of Autonomy. Organic Law 4/1982, of June 9  (BOE no. 146, of June 19), amended by Organic Law 1/1991, of March 13 (BOE no. 146, of June 19 and BOE no. 63, of March 14), by Organic Law 4/1994, of March 24 (BOE no. 72, of March 25), by Organic Law 1/1998, of June 15 (BOE no. 143, of June 16), by Organic Law 7/2013, of November 28 (BOE no. 286, of November 29) and by Organic Law 1/2021, of February 15 (BOE no. 40, of February 16).
• Royal Decree 1276/1994, of June 10, on the transfer of functions and services (BOE no. 154, of June 29).
  

Yes. Sectoral regulations are varied; among them, the following should be mentioned:

• Youth associations
• University student associations
• Sports associations
• Parent associations
• Consumer and user associations

Additionally, those referring to international development cooperation or volunteering should be mentioned.

The minimum number, whether natural or legal persons (duly constituted), is THREE. There is no maximum limit on the number of members. It is understood, in any case, that the intent is to unite the largest number of people to defend and promote the project.

Yes, Organic Law 2/2009 granted this right to all Spaniards and foreigners on equal terms. In any case, they will need to obtain a NIE (Foreigner Identification Number) beforehand (from the appropriate authorities and for such purposes).

A minimum financial or asset contribution is not necessary. In any case, it should be taken into account that it will be necessary to pay registration fees, consultancy fees, etc… so it is advisable to have a plan to cover them.