Every year Swiss companies must issue a standardized salary certificate to employees noting all taxable benefits employees have received during the year. This catches a lot of perks, but there are exceptions that can be useful to know about. Some key benefits of value that an employer can give his staff (even when self-employed) and which do not need to be declared include:

An SBB (CFF) half price travel card

Gifts for Christmas, birthdays or other common gifts so long as the value is not more than CHF 500 on each occasion

Private use of work tools (e.g. mobile phone, computer, etc.)

Membership of clubs or associations that cost no more than CHF 1000 per membership (excludes gym memberships). If the association is a professional one there is no limit

Entry tickets to cultural, sporting or social occasions with a value of not more than CHF 500

Offering a free parking space at the workplace

Courses paid for by the employer, including to change careers, but payments must be made directly from the company to the course provider, and any invoices must be in the name of the company

Lunch allowance with a value of up to CHF 2,160 can be offered. Certain companies offer special card services to account for this (e.g. https://www.swibeco.ch/en/lunch-card/ & https://www.lunch-check.ch/en/home/)

Subsidies which an employer pays to a crèche in order to offer a reduction in price to the employee

Travel costs for a spouse or partner accompanying the employee on a business trip

Finally, remember to always keep receipts for any business trips and have these ready to present in case of an audit