Print all Sundays in 2017
Python 2, 81 bytes



x=0
exec"print'%05.2f.2017'%(x%30.99+1.01);x+=7+'0009ANW'.count(chr(x/7+40));"*53


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No date libraries, computes the dates directly. The main trick is to treat the dd.mm as a decimal value. For example, 16.04.2017 (April 16) corresponds to the number 16.04. The number is printed formatted as xx.xx with  .2017 appended.

The day and month are computed arithmetically. Each week adds 7 days done as x+=7. Taking x modulo 30.99 handles rollover by subtracting 30.99 whenever the day number gets too big. This combines -31 to reset the days with +0.01 to increment the month. 

The rollover assumes each month has 31 days. Months with fewer days are adjusted for by nudging x upwards on certain week numbers with +[8,8,8,17,25,38,47].count(x/7). These list is of the week numbers ending these short months, with 8 tripled because February is 3 days short of 31. 

This list could is compressed into a string by taking ASCII values plus 40. The shift of +40 could be avoided by using unprintable chars, and could be accessed shorter as a bytes object in Python 3.