What are some similar activities that the 5 pillars have to other religions?

Examples from two other religions. Firstly, Christianity.

1 Shahadah

Many Christians recite the Nicene Creed, which states "We believe in one God" and goes on to say Christ his son but also indivisible from Him.

2 Salat

Prayer is central to Christian practice and the Bible has many verses on the necessity and value of prayer.

3 Sawm

There is no month of fasting in Christianity but there are many Bible verses on the value of fasting. Catholicism adopted a practice of refraining from meat on Fridays, and fasting was practiced on pilgrimage. Lent would involve giving up something, often a favourite food, to commemorate Christ's 40-day fast.

4 Zakat

Giving to the poor is expected of Christians, with many Bible verses on it. Some denominations formalised this in a practice called "tithing", where worshippers had to give 10% of their income to the church, which (in theory) the church would use to help the poor.

5 Hajj

Pilgrimage was important to most Christian denominations before the Reformation, and still is for many. Pilgrimages would be made to shrines containing relics of saints. Pilgrimages were also (and still are) made to the Holy Land, to see Jerusalem and other places connected to the life of Christ.

Secondly, Buddhism. As Buddhism does not have a personal creator God, this is a bit different, but there are parallels.

1 Shahadah

Millions of Buddhists recite the Buddha Vandana (praises to the Buddha) daily, which includes the line "all my life I go for Refuge to the Buddha" and "refuge supreme is there for me".

2 Salat

The Buddha recommended daily meditation, which can be seen as equivalent to prayer as it is about trying to link the individual to the transcendental.

3 Sawm

Fasting is an important practice for many Buddhists. For example, Tibetan monks and nuns fast from noon until bedtime. There are a Tibetan Buddhist practice involving total fasting (even from water) on intermittent days.

4 Zakat

The Buddha laid down 5 ethical precepts for his disciples to follow, the 2nd of which calls for "open-handed generosity". This is called Dana, and is a very important practice for Buddhists.

5 Hajj

Many Buddhists go on pilgrimage to sites associated with the Buddha and the Bodhisattvas (loosely, the Buddhist equivalent of saints). The most important place of pilgrimage is Bodh Gaya, the place where the Buddha found enlightenment.